  SEQ CHAPTER \h \r 1 United States			Prevention, Pesticides		EPA
738-R-06-007

Environmental Protection		and Toxic Substances		August 2006

Agency				(7510P) 

Reregistration

Eligibility Decision   

(RED) for Chlorine Dioxide and Sodium Chlorite (Case 4023)

                        

		

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF           

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

CERTIFIED MAIL

							

Dear Registrant: 

	This is to inform you that the Environmental Protection Agency
(hereafter referred to as EPA or the Agency) has completed its review of
the available data and public comments received related to the draft
risk assessments for the antimicrobials, chlorine dioxide and sodium
chlorite.   SEQ CHAPTER \h \r 1  The enclosed Reregistration Eligibility
Decision (RED) document was approved on August 3, 2006.  Public comments
and additional data received were considered in this decision.  

Based on its review, EPA is now publishing its Reregistration
Eligibility Decision (RED) and risk management decision for chlorine
dioxide and sodium chlorite and the associated human health and
environmental risks.  A Notice of Availability will be published in the
Federal Register announcing the publication of the RED.

The RED and supporting risk assessments for chlorine dioxide are
available to the public in EPA’s Pesticide Docket EPA-HQ-OPP-2006-0328
at:   HYPERLINK "http://www.regulations.gov"  http://www.regulations.gov
.  

The chlorine dioxide and sodium chlorite RED was developed through
EPA’s public participation process, published in the Federal Register
on April 26, 2006, which provides opportunities for public involvement
in the Agency’s pesticide tolerance reassessment and reregistration
programs.  Developed in partnership with USDA and with input from
EPA’s advisory committees and others, the public participation process
encourages robust public involvement starting early and continuing
throughout the pesticide risk assessment and risk mitigation
decision-making process.  The public participation process encompasses
full, modified, and streamlined versions that enable the Agency to
tailor the level of review to the level of refinement of the risk
assessments, as well as to the amount of use, risk, public concern, and
complexity associated with each pesticide.  Using the public
participation process, EPA is attaining its strong commitment to both
involve the public and meet statutory deadlines.  

Please note that the chlorine dioxide and sodium chlorite risk
assessment and the attached RED document concern only these particular
pesticides.  This RED presents the Agency’s conclusions on the
dietary, drinking water, residential, occupational and ecological risks
posed by exposure to chlorine dioxide and sodium chlorite alone.  This
document also contains both generic and product-specific data that the
Agency intends to require in Data Call-Ins (DCIs).  Note that DCIs, with
all pertinent instructions, will be sent to registrants at a later date.
 Additionally, for product-specific DCIs, the first set of required
responses will be due 90 days from the receipt of the DCI letter.  The
second set of required responses will be due eight months from the
receipt of the DCI letter.

As part of the RED, the Agency has determined that chlorine dioxide and
sodium chlorite will be eligible for reregistration provided that all
the conditions identified in this document are satisfied, including
implementation of the risk mitigation measures outlined in Section IV of
the document.  Sections IV and V of this RED document describe labeling
amendments for end-use products and data requirements necessary to
implement these mitigation measures.  Instructions for registrants on
submitting the revised labeling can be found in the set of instructions
for product-specific data that accompanies this document.

Should a registrant fail to implement any of the risk mitigation
measures outlined in this document, the Agency will continue to have
concerns about the risks posed by chlorine dioxide and sodium chlorite. 
Where the Agency has identified any unreasonable adverse effect to human
health and the environment, the Agency may at any time initiate
appropriate regulatory action to address this concern.  At that time,
any affected person(s) may challenge the Agency’s action.  

If you have questions on this document or the label changes necessary
for reregistration, please contact the Chemical Review Manager, ShaRon
Carlisle, (703) 308-6427.  For questions about product reregistration
and/or the Product DCI that will follow this document, please contact
Emily Mitchell at (703) 308-8583.

						Sincerely,

						Frank Sanders, Director

						Antimicrobials Division (7510C)



REREGISTRATION ELIGIBILITY

DECISION

for

Chlorine Dioxide and Sodium Chlorite

Case Number 4023

Approved by:

______________________

Frank T. Sanders, Director

Antimicrobials Division 

________________________

Date

TABLE OF CONTENTS 

Glossary of Terms and
Abbreviations……………………………………………..	ix



Chlorine Dioxide Reregistration
Team…………………………………………….	viii



Executive
Summary………………………………………………………
………....	xi



	I.
Introduction……………………………………………………
…………………..	1



II. Chemical
Overview………………………………………………………
…….	..	

3

	A. Regulatory
History……………………………………………………..		3

	B. Chemical Identification
………………………………………………..	3

	C. Use
Profile………………………………………………………
………...	4



III. Summary of Chlorine Dioxide Risk
Assessments……………………………….	

6

	A. Human Health Risk
Assessment………………………………………	6

		1. Toxicity of Chlorine
Dioxide…………………………………….	6

		2. FQPA Safety
………………………………………………………	10

		3. Population Adjusted Dose
(PAD)………………………………...	10

			a. Acute PAD…………………………………………………
11

			b. Chronic PAD……………………………………………		11

		4. Exposure
Assumptions……………………………………………	12

		5. Dietary (Food) Risk
Assessment………………………………….	13

			a. Acute Dietary Risk………………………………………..
13

			b. Chronic (Non-Cancer) Dietary Risk……………………..	16

		6. Dietary Risks from Drinking
Water……………………………..	16

			a. Drinking Water Exposure………………………………..	17

			b. Acute Dietary Risk (Drinking Water)…….……………..	18

			c. Chronic Dietary Risk (Drinking Water)………………..	18

		7. Residential
Exposure...……………………………………………	19

			a.
Toxicity…………………………………………………….	19

			b. Residential Handler…...…………………………………..
21

		i. Exposure Scenarios, Data and Assumptions……..	21

			ii. Residential Handler Risk Estimates……………..	22

			c. Residential Post-application ….………………………….
23

			i. Exposure Scenarios, Data and Assumptions……..	23

ii. Residential Post-Application Risk Estimates….	23

		8. Aggregate
Risk……………………………………………………	25

			a. Acute Aggregate Risk …………………………. ....……..
26

			b. Short and Intermediate Acute Aggregate Risk ………..	26

			c. Chronic Aggregate Risk……………………………..	27

		9. Occupational
Risk………………………………………………...	28

			a. Occupational Toxicity…………………………………….
28

			b. Occupational Handler Exposure…………………………	29

			c. Occupational Handler Risk Summary…………………...	33

			d. Occupational Post-Application Risk Summary…………	36

			e. Human Incident Data……………………………………..	37

	B. Environmental Risk
Assessment………………………………………..	37

		1. Environmental Fate and
Transport……………………………...	38

		2. Ecological
Risk……………………………………………………	38

		3. Listed Species Consideration
…………………………………….	39

			a. The Endangered Species Act…….……………………….	39



IV. Risk Management, Reregistration, and Tolerance Reassessment
Decision…	

41

	A. Determination of Reregistration
Eligibility……………………………	41

	B. Public Comments and
Responses……………………………………….	41

	C. Regulatory
Position………………………………………………………
42

		1. Food Quality Protection Act Considerations…………………...
42

			a. "Risk Cup" Determination……………………………….	 42

			b. Determination of Safety to U.S. Population…………….	43

			c. Determination of Safety to Infants and Children………	43

			d. Endocrine Disruptor Effects……………………………..	43

			e. Cumulative Risks………………………………………….
44

		2. Tolerance
Summary……………………………………………	44

			a. Tolerances Currently Listed and Tolerance 					
Reassessment…………………………………………	45

			b. Codex Harmonization……………………………………	45

	D. Regulatory
Rationale……………………………………………………..
45

		1. Human Health Risk Management……………………………….
45

			a. Dietary (Food) Risk Mitigation………………………….	45

b. Safety Drinking Water Act ……………………………..	45

			c. Drinking Water Risk Mitigation………………………..	48

			d. Residential Risk Mitigation………………………………	49

e. Aggregate Risk Mitigation ……………………………….	50

			f. Occupational Risk Mitigation……………………………	50

				i. Occupational Handler…………………………….	50

		2. Environmental Risk Management…………………………..	52

		3. Other Labeling
Requirements……………………………………	52

		4. Threatened and Endangered Species Considerations…………..	52

			a. The Endangered Species Program……………………….	52

			b. General Risk Mitigation………………………………..	53



V. What Registrants Need to
Do…………………………………………………..	

54

	A. Manufacturing
Use-Products……………………………………………	55

		1. Additional Generic Data Requirements………………………..
55

		2. Labeling for Technical and Manufacturing-Use Products……..	56

	B. End-Use
Products……………………………………………………..
56

		1. Additional Product Specific Data Requirements…………..........
56

		2. Labeling for End-Use
Products…………………………………..	56

			a. Label Changes Summary Table………………………….	58



VI.
Appendices……………………………………………………
………………….	62

	A. Table of Use Patterns for Chlorine
Dioxide……………………………	63

	 Table of Use Patterns for  Sodium Chlorite…………………….	74

	B. Table of Generic Data Requirements and Studies Use to Make the 		
Reregistration
Decision…………………………………………….	

90

	C. Technical Support
Documents…………………………………………	95

	D. Bibliography
Citations………………………………………………….	96

	E. Generic Data
Call-In…………………………………………………….	107

	F. Product Specific Data
Call-In……………………………………………	108

	G. Batching of End-Use
Products………………………………………….	109

	H. List of All Registrants Sent the Data
Call-In…………………………..	110

	I. List of Available
Forms…………………………………………………..	111









Chlorine Dioxide Reregistration Team

Antimicrobials Division

Science Team

Melba Morrow (Science Coordinator)

Timothy McMahon 

Timothy Leighton  

Najm Shamim

Genevieve Angle

Jonathan Chen

Risk Management

ShaRon Carlisle

Diane Isbell

Jennifer Slotnick

Registration Support

Emily Mitchell

Wanda Henson

Office of General Counsel

Erin Koch

Michele Knorr

Glossary of Terms and Abbreviations

a.i.		Active Ingredient

aPAD		Acute Population Adjusted Dose

APHIS		Animal and Plant Health Inspection Service

ARTF		Agricultural Re-entry Task Force

BCF		Bioconcentration Factor

CDC		Centers for Disease Control

CDPR		California Department of Pesticide Regulation 

CFR		Code of Federal Regulations

ChEI		Cholinesterase Inhibition

CMBS		Carbamate Market Basket Survey

cPAD		Chronic Population Adjusted Dose

CSFII		USDA Continuing Surveys for Food Intake by Individuals

CWS		Community Water System

DCI		Data Call-In

DEEM		Dietary Exposure Evaluation Model

DL		Double layer clothing {i.e., coveralls over SL}

DWLOC	Drinking Water Level of Comparison

EC		Emulsifiable Concentrate Formulation

EDSP		Endocrine Disruptor Screening Program

EDSTAC	Endocrine Disruptor Screening and Testing Advisory Committee

EEC		Estimated Environmental Concentration.  The estimated pesticide
concentration in an environment, such as a terrestrial ecosystem.

EP		End-Use Product

EPA		U.S. Environmental Protection Agency

EXAMS		Tier II Surface Water Computer Model  		

FDA		Food and Drug Administration

FFDCA		Federal Food, Drug, and Cosmetic Act

FIFRA		Federal Insecticide, Fungicide, and Rodenticide Act

FOB		Functional Observation Battery	

FQPA		Food Quality Protection Act

FR		Federal Register						

GL		With gloves

GPS		Global Positioning System

HIARC		Hazard Identification Assessment Review Committee

IDFS		Incident Data System

IGR		Insect Growth Regulator

IPM		Integrated Pest Management

RED		Reregistration Eligibility Decision

LADD		Lifetime Average Daily Dose

LC50		Median Lethal Concentration.  Statistically derived concentration
of a substance expected to cause death in 50% of test animals, usually
expressed as the weight of substance per weight or volume of water, air
or feed, e.g., mg/l, mg/kg or ppm.

LCO		Lawn Care Operator

LD50		Median Lethal Dose.  Statistically derived single dose causing
death in 50% of the test animals when administered by the route
indicated (oral, dermal, inhalation), expressed as a weight of substance
per unit weight of animal, e.g., mg/kg.

LOAEC		Lowest Observed Adverse Effect Concentration

LOAEL		Lowest Observed Adverse Effect Level

LOC		Level of Concern

LOEC		Lowest Observed Effect Concentration

mg/kg/day	Milligram Per Kilogram Per Day

MOE		Margin of Exposure 

MP		Manufacturing-Use Product

MRID		Master Record Identification (number).  EPA's system of recording
and tracking studies submitted.

MRL		Maximum Residue Level

N/A		Not Applicable

NASS		National Agricultural Statistical Service

NAWQA	USGS National Water Quality Assessment

NG 		No Gloves

NMFS		National Marine Fisheries Service

NOAEC		No Observed Adverse Effect Concentration

NOAEL		No Observed Adverse Effect Level

NPIC		National Pesticide Information Center

NTP		National Toxicology Program 

NR		No respirator

OP		Organophosphorus

OPP		EPA Office of Pesticide Programs

ORETF		Outdoor Residential Exposure Task Force

PAD		Population Adjusted Dose

PCA		Percent Crop Area

PDCI		Product Specific Data Call-In

PDP		USDA Pesticide Data Program

PF10		Protections factor 10 respirator

PF5		Protection factor 5 respirator

PHED		Pesticide Handler's Exposure Data 

PHI		Preharvest Interval

ppb		Parts Per Billion

PPE		Personal Protective Equipment

PRZM		Pesticide Root Zone Model

RBC		Red Blood Cell

RAC		Raw Agricultural Commodity

RED		Reregistration Eligibility Decision

REI		Restricted Entry Interval

RfD		Reference Dose

RPA		Reasonable and Prudent Alternatives

RPM		Reasonable and Prudent Measures

RQ		Risk Quotient

RTU		(Ready-to-use)

RUP		Restricted Use Pesticide

SCI-GROW	Tier I Ground Water Computer Model

SF		Safety Factor

SL		Single layer clothing

SLN		Special Local Need (Registrations Under Section 24(c) of FIFRA)

STORET	Storage and Retrieval

TEP		Typical End-Use Product

TGAI		Technical Grade Active Ingredient

TRAC 		Tolerance Reassessment Advisory Committee

TTRS		Transferable Turf Residues

UF		Uncertainty Factor

USDA		United States Department of Agriculture

USFWS		United States Fish and Wildlife Service

USGS		United States Geological Survey 

WPS		Worker Protection Standard

Abstract tc "EXECUTIVE SUMMARY" 

	The Environmental Protection Agency (EPA or the Agency) has completed
the human health and environmental risk assessments for Chlorine Dioxide
and Sodium Chlorite and is issuing its risk management decision and
tolerance reassessment.  The risk assessments, which are summarized
below, are based on the review of the required target database
supporting the use patterns of currently registered products and
additional information received through the public docket.  After
considering the risks identified in the revised risk assessments,
comments received, and mitigation suggestions from interested parties,
the Agency developed its risk management decision for uses of chlorine
dioxide and sodium chlorite that pose risks of concern.  As a result of
this review, EPA has determined that chlorine dioxide and sodium
chlorite containing products are eligible for reregistration, provided
that risk mitigation measures are adopted and labels are amended
accordingly.  That decision is discussed fully in this document.  The
Inorganic Chlorates Reregistration Eligibility Decision (RED) (PC code
073301), determined that sodium chlorate tolerances were safe provided a
safety finding could be made for chlorine dioxide and sodium chlorite. 
This decision fulfills that condition.

I.  	Introduction  XE "I. Introduction"  			

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was
amended in 1988 to accelerate the reregistration of products with active
ingredients registered prior to November 1, 1984 and amended again by
the Pesticide Registration Improvement Act of 2003 to set time frames
for the issuance of Reregistration Eligibility Decisions.  The amended
Act calls for the development and submission of data to support the
reregistration of an active ingredient, as well as a review of all
submitted data by the U.S. Environmental Protection Agency (EPA or the
Agency).  Reregistration involves a thorough review of the scientific
database underlying a pesticide’s registration.  The purpose of the
Agency’s review is to reassess the potential hazards arising from the
currently registered uses of the pesticide; to determine the need for
additional data on health and environmental effects; and to determine
whether or not the pesticide meets the “no unreasonable adverse
effects” criteria of FIFRA.

On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was
signed into law.  This Act amends FIFRA to require reregistration
assessments of the prior to 1984 chemicals.  The Agency has decided
that, for those chemicals that have tolerances and are undergoing
reregistration, the tolerance reassessment will be initiated through
this reregistration process.  The Act also requires that by 2006, EPA
must review all tolerances in effect on the day before the date of the
enactment of the FQPA.  FQPA also amends the Federal Food, Drug, and
Cosmetic Act (FFDCA) to require a safety finding in tolerance
reassessment based on factors including consideration of cumulative
effects of chemicals with a common mechanism of toxicity.  This document
presents the Agency’s revised human health and ecological risk
assessments; and the Reregistration Eligibility Decision (RED) for
chlorine dioxide and sodium chlorite.

	Chlorine dioxide and sodium chlorite are active ingredients in numerous
products used in the control of bacteria, fungi, and algal slimes.  In
addition, chlorine dioxide and sodium chlorite are used as material
preservatives and as disinfectants.  At this time, products containing
chlorine dioxide and sodium chlorite are intended for agricultural,
commercial, industrial, medical and residential use.  The agricultural
premises and equipment uses include the disinfection of hard surfaces
and equipment (such as hatching facilities and mushroom houses) and
water systems (such as chiller water and humidification water in poultry
houses).  Commercial, industrial, and medical uses include disinfection
of ventilation systems, hard surfaces (e.g., floors, walls, and
laboratory equipment), water systems, pulp/paper mills, and food rinses.
 Residential uses include disinfection of hard surfaces (e.g., floors,
bathrooms), heating ventilating and air-conditioning (HVAC) systems, and
treatment of pool & spa water circulation systems.  In addition, there
is a continuous release gas product (sachet) for the home to control
odors. 

	The Agency has concluded that the FQPA Safety Factor for chlorine
dioxide should be removed (equivalent to 1X) based on: (1) the existence
of a complete developmental and reproductive toxicity database; (2) the
endpoint selected for assessment of risk from dietary and non-dietary
exposure to chlorine dioxide is protective of potentially susceptible
populations including children and (3) the risk assessment does not
underestimate the potential exposure for infants and children.  

Risks summarized in this document are those that result only from the
use of the active ingredients chlorine dioxide and sodium chlorite.  The
FFDCA requires that the Agency consider available information concerning
the cumulative effects of a particular pesticide’s residues and other
substances that have a common mechanism of toxicity.  The reason for
consideration of other substances is due to the possibility that
low-level exposures to multiple chemical substances that cause a common
toxic effect by a common toxic mechanism could lead to the same adverse
health effect that would occur at a higher level of exposure to any of
the substances individually.  Unlike other pesticides for which EPA has
followed a cumulative risk approach based on a common mechanism of
toxicity, EPA has not made a common mechanism of toxicity finding for
chlorine dioxide and sodium chlorite and any other substances.  
Chlorine dioxide and sodium chlorite do not appear to produce a toxic
metabolite produced by other substances.  For the purposes of this
action, therefore, EPA has not assumed that chlorine dioxide and sodium
chlorite has a common mechanism of toxicity with other substances.  For
information regarding EPA’s efforts to determine which chemicals have
a common mechanism of toxicity and to evaluate the cumulative effects of
such chemicals, see the policy statements released by EPA’s Office of
Pesticide Programs concerning common mechanism determinations and
procedures for cumulating effects from substances found to have a common
mechanism on EPA’s website at   HYPERLINK
"http://www.epa.gov/pesticides/cumulative" 
http://www.epa.gov/pesticides/cumulative  .

This document presents the Agency’s decision regarding the
reregistration eligibility of the registered uses of chlorine dioxide
and sodium chlorite.  In an effort to simplify the RED, the information
presented herein is summarized from more detailed information which can
be found in the technical supporting documents for chlorine dioxide and
sodium chlorite referenced in this RED.  The revised risk assessments
and related addenda are not included in this document, but are available
in the Public Docket at     HYPERLINK "http://www.epa.gov/edocket" 
http://www.epa.gov/edocket  (EPA-HQ-OPP-2006-0328).

This document consists of six sections.  Section I is the introduction. 
Section II provides a chemical overview, a profile of the use and usage
of chlorine dioxide and sodium chlorite and its regulatory history. 
Section III, Summary of Chlorine Dioxide and Sodium Chlorite Risk
Assessment, gives an overview of the human health and environmental
assessments, based on the data available to the Agency.  Section IV,
Risk Management, Reregistration, and Tolerance Reassessment Decision,
presents the reregistration eligibility and risk management decisions. 
Section V, What Registrants Need to Do, summarizes the necessary label
changes based on the risk mitigation measures outlined in Section IV. 
Finally, the Appendices list all use patterns eligible for
reregistration, bibliographic information, related documents and how to
access them, and Data Call-In (DCI) information.  

II.	Chemical Overview

	A.	Regulatory History

EPA first registered the aqueous form of chlorine dioxide for use as a
disinfectant and a sanitizer in 1967.  In industrial processes, chlorine
dioxide is used as a disinfectant in water treatment, ammonia plants,
pulp mills, oil fields, scrubbing systems, odor control systems, and the
electronics industry.  In 1988, EPA registered chlorine dioxide gas as a
sterilant.  Chlorine dioxide gas is registered for sterilizing
manufacturing and laboratory equipment, environmental surfaces, tools,
and clean rooms.  One of the major antimicrobial uses of chlorine
dioxide is to treat drinking water.  In addition, the largest use of
chlorine dioxide is the non-pesticidal bleaching use in the pulp and
paper industry.

Both sodium chlorite and the active ingredient sodium chlorate are used
as a precursor in the generation of chlorine dioxide.  Sodium chlorite
is a strong oxidizing agent that under oxidizing conditions is readily
reduced to chlorite, another strong oxidizing agent, and to a lesser
extent, chlorate.  Sodium chlorate (included in the group of inorganic
chlorates) is predominantly used in the pulp and paper manufacturing
process and as a herbicide in agriculture.  The antimicrobial uses of
sodium chlorate are a minor part of the use pattern.  The uses of sodium
chlorate were assessed separately in the Inorganic Chlorates
Reregistration Eligibility Decision (RED) (PC code 073301).  The RED for
the inorganic chlorates is available in the public docket at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  in docket number
EPA-HQ-OPP-2005-0507.  This RED will focus on the uses of chlorine
dioxide/sodium chlorite. 

	

	B.	Chemical Identification 

CHLORINE DIOXIDE: PHYSICAL/CHEMICAL CHARACTERISTICS

Chemical Name:		Chlorine dioxide, Chlorine (IV) oxide

Chemical Formula:		ClO2

 

CAS#:				10049-04-4

Molecular Weight:		67.45 g/mol

Color:                                      Gas phase- Yellow green to
orange

                                                 Liquid phase- reddish
brown				

Melting Point:			-59 o C

Boiling Point:			11 o C

Odor:				Strongly pungent, chlorine-like

Physical State:			Gas at room temperature

Density:			1.64 g/ml at 0 o C (liquid)

				1.614 g/ml at 10 o C (liquid)

Vapor Pressure:		490 mm Hg (0o C)

				>760 mm Hg (25 o C)

Stability:			Unstable, estimated half life in water ~ 25 minutes*

Solubility (water):		3.01 g/L at 25 o C and 34. 5 mm Hg**

Chlorine dioxide is explosive at > -40 o C, and its explosive velocity
in air is 50 m/s.  It is highly miscible in water up to 60 g/L and is
highly unstable in sunlight.

In aqueous solutions at pH>10, chlorine dioxide will hydrolyze to form
chlorate and chlorite ions.  In neutral or near neutral solutions (4< pH
<10) chlorine dioxide is relatively stable and exists as a free radical
in water.  The rate of the hydrolysis reaction between water and
chlorine dioxide is about ten million times slower than that of chlorine
at neutral pH.

SODIUM CHLORITE: PHYSICAL/CHEMICAL CHARACTERISTICS 

Chemical Name:		Sodium chlorite

Synonyms(s):			Chlorous acid, sodium salt

Chemical Formula:		NaClO2

 

CAS#:				7758-19-2

Molecular Weight:		90.45 g/mol

Color:				White

Melting Point:			180-200 o C (decomposes)

Boiling Point:			n/a

Physical State:			Solid

Density:			2.468 g/ml (as a solid)

Vapor Pressure:		n/a

Stability:			Stable at Room Temperature

Solubility (water):		390 g/L at 30 o C

Compatibility:	Incompatible with organic matter, sulfur, powdered coal,
and is a powerful oxidizer.

	C.	Use Profile

	The following is information on the currently registered uses of
chlorine dioxide and sodium chlorite, including an overview of use sites
and application methods.  A detailed table of the uses of sodium
chlorate eligible for reregistration is available in Appendix A.



Type of Pesticide: 			Antimicrobial

Target Pests:			Bacteria, fungi, and algal slimes.

Use Site:	

Agricultural uses:	The agricultural premises and equipment uses include
the disinfection of hard surfaces and equipment (such as hatching
facilities and mushroom houses) and water systems (such as chiller water
and humidification water in poultry houses).  

Non-agricultural uses:	Commercial, industrial, and medical uses include
disinfection of ventilation systems, hard surfaces (e.g., floors, walls,
and laboratory equipment), water systems, pulp/paper mills, and food
rinses

Residential:	Residential uses include disinfection of hard surfaces
(e.g., floors, bathrooms), heating ventilating and air-conditioning
(HVAC) systems, and treatment of pool & spa circulation systems.  In
addition, there is a continuous release gas product (sachet) for the
home to control odors.

Use Classification:	General Use

Method and Rates of Application: 

Equipment:	Foaming wand, sprayer, injector systems, mist and fogger, dip
carcass, mop, pump, cloth and add to systems

Application Rates:	Concentrations of chlorine dioxide and sodium
chlorite range from 5ppm to 5000ppm 

Formulation Types:			Soluble concentrates and ready-to-use liquid
solutions 

III.	Summary of Chlorine Dioxide and Sodium Chlorite Risk Assessments

The purpose of this summary is to assist the reader by identifying the
key features and findings of these risk assessments, and to help the
reader better understand the conclusions reached in the assessments. 
The human health and ecological risk assessment documents and supporting
information listed in Appendix C were used to formulate the safety
finding and regulatory decision for chlorine dioxide and sodium
chlorite.  While the risk assessments and related addenda are not
included in this document, they are available from the OPP Public
Docket, located at   HYPERLINK "http://www.regulations.gov" 
http://www.regulations.gov , under docket number EPA-HQ-OPP-2006-0328. 
Hard copies of these documents may be found in the OPP public docket
under this same docket number.  The OPP public docket is located in Room
S-4400, One Potomac Yard (South Building), 2777 South Crystal Drive,
Arlington, VA, 22202 and is open Monday through Friday, excluding
Federal holidays, from 8:30 a.m. to 4:00 p.m.

	A.	Human Health Risk Assessment

	The human health risk assessment for chlorine dioxide and sodium
chlorite incorporates potential exposure and risks from all sources,
which include food, drinking water, residential (if applicable), and
occupational scenarios.  Aggregate assessments combine food, drinking
water, and any residential or other non-occupational (if applicable)
exposures to determine potential exposures to the U.S. population.  The
Agency’s human health assessment is protective of all U.S.
populations, including infants and young children.  For more information
on the chlorine dioxide and sodium chlorite human health risk
assessment, see Revised Chlorine Dioxide Risk Assessment, dated July 27,
2006, available at   HYPERLINK "http://www.regulations.gov" 
www.regulations.gov  (EPA-HQ-OPP-2006-0328).

	The Agency’s use of human studies in the sodium chlorite risk
assessment is in accordance with the Agency's Final Rule promulgated on
January 26, 2006, related to Protections for Subjects in Human Research,
which is codified in 40 CFR Part 26.  

		1.	Toxicity of Chlorine Dioxide and Sodium Chlorite

	A brief overview of the toxicity studies used for determining endpoints
in the dietary risk assessments are outlined in Table 2.  The Agency has
reviewed all toxicity studies submitted for chlorine dioxide and has
determined that the toxicological database is complete, reliable, and
sufficient for reregistration.  For more details on the toxicity and
carcinogenicity of the chlorine dioxide and sodium chlorite, see the
Chlorine Dioxide Toxicology Disciplinary Chapter, Case 4023, dated
April, 5, 2006, which is available under docket number
EPA-HQ-OPP-2006-0328.

Major features of the toxicology profile are presented below. The acute
toxicity of chlorine dioxide is moderate by the oral route (toxicity
category II).  The acute toxicity of chlorine dioxide using sodium
chlorite as the test material is considered minimal by the dermal route
(toxicity category III).  By the inhalation route using sodium chlorite
as the test material, chlorine dioxide was moderately toxic. For primary
eye irritation, chlorine dioxide was a mild irritant (toxicity category
III), but the technical test material was not used.  For primary dermal
irritation, sodium chlorite was a primary irritant (toxicity category
II).  For dermal sensitization, there are no acceptable studies for
chlorine dioxide or sodium chlorite.  The acute toxicity profile for
chlorine dioxide is summarized in Table 1 below.



Table 1.  Acute Toxicity Profile for Chlorine Dioxide/ Sodium Chlorite

Guideline Number	Study Typea / Test substance (% a.i.)	MRID Number/
Citation	Results	Toxicity Category

870.1100

(§81-1)	Acute oral

(79% chlorine dioxide)	43558601	LD50 = 292 mg/kg (males)

LD50 = 340 mg/kg (females)	II

870.1200

(§81-2)	Acute dermal

(80% sodium chlorite)	40168704	LD50 > 2000 mg/kg	III

870.1300

(§81-3)	Acute inhalation

(80.6% sodium chlorite)	42484101	LC50 = 0.29 mg/L	II

870.2400

(§81-4)	Primary eye irritation

(2% chlorine dioxide)	43441903	Mild irritant	III

870.2500

(§81-5)	Primary dermal irritation

(80% sodium chlorite)	40168704	Primary irritant	II

870.2600

(§81-6)	Dermal sensitization	No acceptable sensitization study
available.

a The available acute studies are all graded as acceptable.  An
acceptable dermal sensitization study is not available in the database. 


The doses and toxicological endpoints selected for the dietary exposure
scenarios are summarized in Table 2 below.

Table 2: Summary of Toxicological Doses and Endpoint Selection for 

Chlorine Dioxide/ Sodium Chlorite

Exposure Scenario	Dose Used in Risk Assessment (mg/kg/day)	UF/MOE for
Risk Assessment	Study and Toxicological Effects

Acute Dietary	  SEQ CHAPTER \h \r 1 An acute dietary endpoint was not
identified in the database for chlorine dioxide.  This risk assessment
is not required.



Chronic Dietary	NOAEL = 3 mg/kg/day	UF = 100 (10x inter-species
extrapolation, 10x intra-species variation)

Chronic  PAD = 0.03 mg/kg/day	Two-generation reproduction toxicity study
(CMA, 1996) - decreases in absolute brain and liver weight, and lowered
auditory startle amplitude at LOAEL of 6 mg/kg/day

Developmental Toxicity - Rat (Orme et al., 1985)- neurobehavioral and
exploratory deficits in rat pups 

Carcinogenicity	No cancer data is available for chlorine dioxide.  



General Toxicity Observations 

Subchronic

Subchronic oral toxicity studies conducted with chlorine dioxide showed
significant reductions in body weight increases and decreases in food
consumption at 200 mg/L, the highest dose tested.  Significant
reductions in water consumption were observed in males and in females. 
Absolute liver weights were decreased in males at ( 50 mg/L, and
absolute spleen weights were decreased in females at ( 25 mg/L.   The
LOAEL is 25 mg/L, based on a significant increase in the incidence of
nasal lesions.  No exposure-related deaths were reported in this study. 


Subchronic oral toxicity studies conducted with sodium chlorite showed
increased salivation, significantly decreased erythrocyte counts, and
decreased total serum protein levels, and effects in the blood.  During
this study four animals died during treatment.  It should be noted that
one exposure-related death was observed in a range-finding study for the
subchronic oral toxicity study each sex in the 200 mg/kg/day group on
treatment days 2 and 3.  

Dietary 

	An acute dietary endpoint was not identified in the database for
chlorine dioxide; this risk assessment is not required for chlorine
dioxide/sodium chlorite.  The chronic dietary endpoint is 3 mg/kg/day,
based on decreases in absolute brain and liver weight, and lowered
auditory startle amplitude at LOAEL of 6 mg/kg/day in a two-generation
reproduction toxicity study and is supported by a developmental toxicity
study in rats.  The target MOE is 100 for all dietary exposures.    

Incidental Oral

	The short-and intermediate-term oral endpoint is 3 mg/kg/day, based on
decreases in absolute brain and liver weight, and lowered auditory
startle amplitude at LOAEL of 6 mg/kg/day in a two-generation
reproduction toxicity study and is supported by a developmental toxicity
study in rats.  The target MOE is 100 for all incidental oral exposures.


Dermal

	The short-, intermediate-, and chronic-term dermal endpoint is based on
decreases in absolute brain and liver weight, and lowered auditory
startle amplitude at LOAEL of 6 mg/kg/day in a two-generation
reproduction toxicity study and is supported by a developmental toxicity
study in rats.  The target MOE is 100 for all dermal exposures. 

Inhalation

The inhalation route of exposure to chlorine dioxide is assessed for
three distinct subpopulations:  (1) occupational exposures (8 hours/day,
5 days/week), (2) one-time exposures for residential uses (e.g., HVAC
systems, mopping floors, etc), and (3) long-term exposure for continuous
release products in the home (24 hours/day, 7 days/week).  Several
animal studies were used to develop reference concentrations (RfCs). 
The effects seen at various concentrations include rhinorrhea, altered
respiration, respiratory infection, bronchial inflammation, alveolar
congestion and hemorrhage, vascular congestion, and peribronchiolar
edema.  Readers are referred to USEPA (2000a) for a detailed review of
the effects seen at specific concentrations and exposure durations along
with the derivation of the RfC.  In summary, the occupational RfC is
determined to be 0.003 ppm and represents an 8-hour time weighted
average (TWA).  The one-time residential exposure scenario is
represented by the RfC of 0.05 ppm and the RfC for long-term, continuous
exposure is 0.00007 ppm.  The RfC methodology incorporates the
uncertainty factors into the concentration.  For inhalation, the RfC is
compared directly to the air concentration of interest.  Inhalation
risks are of concern if the air concentrations people are exposed to
exceed the RfC.

	

Carcinogenicity   

Chlorine dioxide has not been assessed for carcinogenic   SEQ CHAPTER \h
\r 1 potential.  The available dermal carcinogenicity studies do not
definitively characterize the carcinogenicity of chlorine dioxide, and
additional studies are required, and will be included in a data call-in
(DCI) to follow this RED.  One subchronic rat study, examined the
effects of administration of chlorine dioxide at dose levels of 0, 25,
50, 100, or 200 mg/L for 90 days in drinking water.  In this subchronic
rat study, a significant increase in the incidence of nasal lesions was
found at all dose levels tested.  The significance of these findings is
uncertain, as they have not been observed in other long-term studies of
chlorine dioxide. 

Mutagenicity

The Agency reviewed data from submitted studies as well as open
literature.  Data on the mutagenicity of chlorine dioxide indicate that
negative effects were reported in one study from a 400-fold drinking
water concentrate of chlorine dioxide, whereas a 4000-fold concentrate
was mutagenic only in the absence of metabolic activation.  In another
study, chlorine dioxide was positive for forward mutations under
non-activated conditions.  Chlorine dioxide was positive for structural
chromosome aberrations under non-activated and activated conditions and
was negative for increased transformed foci up to cytotoxic levels.  In
one mouse study on chlorine dioxide, In vivo micronucleus and bone
marrow chromosomal aberration assays were negative, as was a sperm-head
abnormality assay.

Developmental/Reproductive

One developmental toxicity study conducted using rats was conducted for
chlorine dioxide and sodium chlorite.  In this study, a NOAEL of 20 mg/L
was established based on decreased exploratory and locomotor activities
in the offspring of rats exposed to chlorine dioxide in drinking water. 
Another developmental toxicity study conducted in rabbits using sodium
chlorite established a NOAEL for developmental and maternal toxicity at
200 ppm, based on a dose-related increase of does with reduced fecal
output during the dosing period, consistent with decreased food
consumption.   

A two-generational reproductive toxicity study was performed using
sodium chlorite.  The NOAEL for this study is 35 ppm (2.9 mg/kg-day) and
the LOAEL is 70 ppm (5.9 mg/kg-day chlorite) based on lowered auditory
startle amplitude and absolute brain weights in two generations.  There
were no significant effects of chlorine dioxide on body weight of dams
or pups at any dose level tested.  

Endocrine Disruption Potential

EPA is required under the FFDCA, as amended by FQPA, to develop a
screening program to determine whether certain substances (including all
pesticide active and other ingredients) “may have an effect in humans
that is similar to an effect produced by a naturally occurring estrogen,
or other such endocrine effects as the Administrator may designate.”
 Following recommendations of its Endocrine Disruptor and Testing
Advisory Committee (EDSTAC), EPA determined that there was a scientific
basis for including, as part of the program, the androgen and thyroid
hormone systems, in addition to the estrogen hormone system.  EPA also
adopted EDSTAC’s recommendation that the Program include evaluations
of potential effects in wildlife.  For pesticide chemicals, EPA will
use FIFRA and, to the extent that effects in wildlife may help determine
whether a substance may have an effect in humans, FFDCA authority to
require the wildlife evaluations.  As the science develops and
resources allow, screening of additional hormone systems may be added to
the Endocrine Disruptor Screening Program (EDSP).

FQPA Safety Factor Considerations 

The FQPA Safety Factor (as required by FQPA) is intended to provide an
additional 10-fold safety factor (10X), to protect for special
sensitivity in infants and children to specific pesticide residues in
food, drinking water, or residential exposures, or to compensate for an
incomplete database.  For chlorine dioxide and sodium chlorite, the FQPA
Safety Factor has been removed (i.e., reduced to 1X).  This safety
factor has been removed because the endpoint selected for both dietary
and non-dietary exposures was based upon adverse effects observed in
offspring from developmental and reproductive toxicity data.  This
approach is consistent with that used by the EPA’s Office of Water for
use of chlorine dioxide as a drinking water disinfectant (Federal
Register Vol. 63, No. 61, pages 15673-15692, March 31, 1998) and the
updated guidance on selection of a safety factor under FQPA.  The
endpoint selected for assessment of risk from dietary and non-dietary
exposure to chlorine dioxide and sodium chlorite is believed to be
protective of potentially susceptible populations, including children,
based upon the selection of an endpoint and effects observed in
offspring and the use of a NOAEL value based on those effects. 
Therefore, it was concluded that an additional safety factor under FQPA
is not necessary in this case.  Further, the risk assessment does not
underestimate the potential exposure for infants and children.  

3.	Population Adjusted Dose (PAD)

Dietary risk is characterized in terms of the Population Adjusted Dose
(PAD), which reflects the reference dose (RfD), either acute or chronic,
that has been adjusted to account for the FQPA Safety Factor (SF).  This
calculation is performed for each population subgroup.  A risk estimate
that is less than 100% of the acute or chronic PAD is not of concern.

a.	Acute PAD  XE "III. Summary of 2,4-DB Risk Assessments:A. Human
Health Risk Assessment: 3. Population Adjusted Dose (PAD): a. Acute PAD"
 

Acute dietary risk is assessed by comparing acute dietary exposure
estimates (in mg/kg/day) to the acute Population Adjusted Dose (aPAD). 
Acute dietary risk is expressed as a percent of the aPAD.  The aPAD is
the acute reference dose, modified by the FQPA safety factor. Although
several studies were considered, an acute reference dose (aRfD) was not
identified for chlorine dioxide.  None of the available studies provided
an endpoint of toxicity attributable to a single exposure. Therefore, no
acute dietary endpoint for chlorine dioxide and sodium chlorite was
selected.

b.	Chronic PAD  XE "III. Summary of 2,4-DB Risk Assessments:A. Human
Health Risk Assessment: 3. Population Adjusted Dose (PAD): a. Acute PAD"
 

	Chronic dietary risk for chlorine dioxide is assessed by comparing
chronic dietary exposure estimates (in mg/kg/day) to the chronic
Population Adjusted Dose (cPAD).  Chronic dietary risk is expressed as a
percent of the cPAD.  The cPAD is the chronic reference dose modified by
the FQPA safety factor.  The cPAD was derived from a two-generation
reproduction toxicity study and a developmental toxicity study in which
the NOAEL (3 mg/kg/day) and LOAEL (6 mg/kg/day) were determined. The
chlorine dioxide and sodium chlorite cPAD is 0.03 mg/kg/day based on a
reference does of 0.03 mg/kg/day, which incorporates the FQPA safety
factor (1X) for the overall U.S. population and all population
subgroups.  

Metabolites and Degradates 

Sodium chlorite is a strong oxidizing agent and under proper reducing
conditions is readily reduced to chloride, and to a lesser extent,
chlorate.  In strong acidic conditions, chlorite can change into
chlorine dioxide.  The main source of chlorite ion exposure in the soil,
water, or indirect food contacts is through the disinfectant
applications.  However, it is likely that some chlorate in these media
is formed through use of antimicrobial applications (disinfectant) of
chlorine dioxide, sodium chlorite, and sodium/calcium hypochlorites.

In aqueous media, these oxyanions (chlorite, chlorate, and hypochlorite)
exist because of the unique chemistry of chlorine, that has a tendency
to change its oxidation states (charges).  Thus, in chlorate, chlorine
has a +5 charge, in chlorite it bears a +3 charge, in hypochlorite a + 1
charge, while in chloride a net -1 charge exists.  These variations in
charges (hence the speciations) are dependent on factors such as:  pH of
the medium, temperature, redox potential of the medium, presence of
oxidizing or reducing species, etc.  Similarly, chlorate itself can
undergo redox reactions, depending on the pH of the aqueous medium to
form, chloride, chlorine, hypochlorite, chlorous acid, chlorine dioxide.

The Agency lacks data that would quantify the interconversions between
chlorate, chlorine dioxide, sodium chlorite, and sodium/calcium
hypochlorite.  Simultaneous conversions of these species are not likely
to occur as these factors (mentioned above) do not work in tandem.  Thus
at this time, any additional dietary risks from interconversions in
drinking water (non-cancer risks), and food (non-cancer risks) cannot be
estimated.  The Agency has included the highest possible dietary
contribution of chlorite ion from use of sodium chlorate from the most
sensitive subpopulation in the dietary risk estimates of sodium
chlorite.  Therefore, the Agency has conservatively determined that
there are no additional risks other than the ones that have been
estimated in chlorine dioxide/sodium chlorite Risk Assessment and sodium
chlorate RED.

	The inorganic chlorates were evaluated in the Inorganic Chlorates
Reregistration Eligibility Decision (case number 4049) (hereinafter
referred to as the “Inorganic Chlorates RED”).  That assessment
considered the contribution of chlorate ion from the use of chlorine
dioxide and sodium chlorate.  Please see Revised Sodium Chlorite Risk
Assessment, dated July 27, 2006, for additional details.

4.     Exposure Assumptions  XE "III. Summary of 2,4-DB Risk
Assessments:A. Human Health Risk Assessment: 3. Population Adjusted Dose
(PAD)"  

	

	The use of chlorine dioxide and sodium chlorite on food or feed contact
surfaces, agricultural commodities, in animal premises and poultry
premises including hatcheries and application to food-grade eggs may
result in pesticide residues in human food.  No residue chemistry data
were required to support these uses in the past; therefore, no residue
data was available for the assessment of these uses

To estimate chlorine dioxide residues on food due to migration of this
chemical from sanitizing and/or disinfecting hard non-porous surfaces,
the Agency has used the US Food and Drug Administration (FDA) model to
determine the Estimated Daily Intake (EDI).  Potential use sites
include: (1) poultry hatcheries, (2) food handling establishments, (3)
post-harvest potato treatments, (4) poultry house disinfection, poultry
chiller water/carcass spray or dip, (5) food processing plants (meat and
fish), (6) dairies, breweries, and bottling plants, and (7) pulp/paper,
polymer slurries, paper adhesive, and paper coating.  The EDI
calculations presented in this assessment assumes that food can contact
2,000 cm2 or 4,000 cm2 (50% and 100% respectively of the FDA worst case
scenario) of treated surfaces, and that 10% of the pesticide would
migrate to food.  The use of the 10% transfer rate, instead of the 100%
transfer rate was used for all indirect food contact surfaces except for
food bottling and packaging surfaces.  The 10% migration rate is based
on Agency Residential Standard Operation Procedures.  These daily
estimates were conservatively used to assess both acute (i.e. percent
acute population adjusted dose or %aPAD) and chronic dietary risks (i.e.
percent chronic population adjusted dose or %cPAD).  The maximum
application rate of 1000 ppm for chlorine dioxide from the various
labeled products was used.  Additional details about the dietary
assessment can be found in “Dietary Risk Assessment for Chlorine
Dioxide and Sodium Chlorite Indoor Uses as Disinfectants/Sanitizers,”
dated July 22, 2006.

	The Agency has conservatively added the highest chronic dietary
exposure to chlorite ion from consumption of food treated with inorganic
chlorates to the total chronic dietary exposure from chlorine
dioxide/sodium chlorite.  This assumes that all residues on food
resulting from the use of inorganic chlorates are sodium chlorite.  The
Agency has decided to include these exposures as part of the chlorine
dioxide/sodium chlorite dietary assessment in order to ensure that the
most conservative dietary assumptions are used.  The inclusion of these
exposures is considered to be highly conservative because it is unlikely
that significant chlorite residues will result from the use of inorganic
chlorates on food crops.  As mentioned previously, the inorganic
chlorates have been reassessed separately from chlorine dioxide.  

There is no evidence that there will be residues of chlorine dioxide or
sodium chlorite in mushrooms following its use as a mushroom house
disinfectant.  Further, if dietary exposures from mushroom house uses
occurred they would be expected to be much lower than the dietary
exposures resulting from the surface disinfectant and sanitizing uses. 
The labels associated with mushroom house use state that the product is
not to be applied to the mushroom crop, compost or casing and that
treated surfaces are to be rinsed with potable water before contact with
the crop, compost or casing.  Because any potential exposures would not
likely pose risks of concern and the sanitizing uses represent a
worst-case scenario, these uses were not assessed.   

	

5.    Dietary (Food) Risk Assessment 

The Agency conducted a dietary exposure/risk assessment for chlorine
dioxide and sodium chlorite.  Generally, a dietary risk estimate that is
less than 100% of the acute or chronic PAD does not exceed the
Agency’s risk concerns.  A summary of acute and chronic risk estimates
are shown in Table 3. 

			a.  	Acute Dietary Risk   XE "III. Summary of 2,4-DB Risk
Assessments:5. Dietary (Food) Risk Assessment: a. Acute Dietary Risk"  	

No acute dietary endpoint was selected because effects attributable to a
single dose were not seen in the available data; therefore, an acute
dietary risk assessment was not conducted.  

b.  	Chronic Dietary Risk

A chronic dietary risk assessment was conducted for chlorine
dioxide/sodium chlorite direct and indirect application to food.  For
indirect food applications, the highest individual subpopulation percent
cPAD calculated is 4.2% for children’s consumption of milk.  For
direct food uses, the chronic risk from the post-harvest use of fruit
and vegetable washes is 42% of the cPAD for children.  For the chlorite
exposure resulting from the use of inorganic chlorate application to
agricultural crops, exposure to children (most highly exposed
subpopulation) resulted in risk estimate of 28 % of the cPAD.  As a
conservative measure, the dietary risk estimates of sodium chlorite
include the highest dietary risk estimate for sodium chlorate for the
most sensitive subpopulation.  

Although there is not a concern for chronic dietary risk estimates
alone, it is important to note that the individual exposure received
from the post-harvest application of sodium chlorite to fruits and
vegetables is an extremely high-end estimate.  This assessment was
conducted with the most conservative assumptions and resulted in an
estimate of 42% of the cPAD for children ages 1-2.   For example, this
assessment assumed that all fruits and vegetables in the U.S. had a
chlorine dioxide solution applied and that these commodities were not
washed, cooked or processed prior to consumption.  However, the Chlorine
Dioxide Panel has agreed to limit the residual concentration of chlorine
dioxide to 3 ppm for post-harvest application to fruits and vegetables
that are not Raw Agricultural Commodities.  In order to get to this
residual, the panel has agreed to label restrictions that require that
fruits and vegetables treated with chlorine dioxide must be blanched,
cooked, or canned before consumption or distribution in commerce. 
Although the Agency cannot quantify the reduction of chlorine dioxide
dietary exposure resulting from this mitigation measure at this time, it
is believed that this measure would significantly reduce the percent of
chlorine dioxide cPAD resulting from this use. 

	The dietary risks for adult and children from food uses are shown in
Table 3.  As there is no acute dietary endpoint for chlorine dioxide,
only chronic dietary risk is presented.  For adults, the total chronic
dietary risk is 9.1% of the cPAD and is not of concern.  For children
(1–2 years), and infants less than 1 year old, the total dietary
exposure is 76%, and 32% of the cPAD, respectively.  These risks are
below the Agency’s level of concern, less than 100% of the cPAD.  As
stated above, this risk scenario is very conservative.  For example, the
Agency does not believe that 100% treatment of fruits and vegetables is
a realistic scenario.  If 50% of this food is treated, which we think is
still unrealistic, the cPad for children (1-2 years) would be
approximately 54%.  The Agency will issue a DCI requiring data be
submitted on how much food is washed with these pesticides.

Table 3.  Summary of Dietary Exposure and Risk for Chlorine Dioxide

Use Site	Food Type	Population Subgroup	EDI (mg/person/day)	Chronic
Dietary





Dietary Exposurea (mg/kg/day)	% cPAD b

Indirect Food Use

Food handling establishments/ kitchens	NA	Adult	2.00 x 10-1	9.5E-07
0.00316



Child

8.8E-06	0.0293

Dairies, Breweries, Bottling Plants, Food Contact Surfaces/Food
Processing Plants for Meats and Fishd	Beverages, alcoholic, beer	Adult
1.2 x 10-3	1.70E-05	0.56

	Beverages, non-alcoholic	Adult	1.6 x 10-3	2.40E-05	0.08



Child

1.00E-04	0.33

	Egg Products, Mayonnaise	Adult	1.4 x 10-4	2.00E-06	0.0086



Child

9.33E-06	0.031

	Milk	Adult	1.9 x 10-2	2.70E-04	0.66



Child

1.30E-03	4.2

Pulp/Paper, Polymer Slurries, Paper Adhesive, Paper Coating	NA	Adult	1.1
x 10-1	9.8E-05	0.326 



Child

2.3E-04	0.766

Total Indirect Food-Contact Exposure	Adult	3.3 x 10-1	4.12E-04	1.64

	Child

1-2 years	2.7 x 10-1	1.65E-03	5.35

	Infant

<1

	<5.35 f

Direct Food Use

Post Harvest Application 	Fruit and Vegetable Wash	Adult	 	2.24E-03c,
e	7.5



Child	 	1.27E-02 c, e	42.3

Total Direct Food-Contact Exposure	Adult	 	2.24E-03	7.5

	Child

1-2 years 	 	1.27E-02	42.3g

	Infant

<1

3.49E-03	11.6 f

Inorganic Chlorate Use

Highest Exposure from 

Agricultural Use	Child 

1 – 2 years

	 	8.38E-03c	28

	Infant 

<1 year

4.511E-03	15 f

Total Dietary Exposure

Total Direct and Indirect Food-Contact Exposure	Adult	 	2.65E-03	9.1

	Child 

1-2 years	 	2.27E-02	75.7

	Infant

<1 year

	<31.95 f

a-- For adults, acute and chronic exposure analysis is based on a body
weight of 70 kg.  For adult females, the body weight is 60 kg.  For
children, exposure is based on a body weight of 15 kg.  

b--%PAD = dietary exposure (mg/kg/day) * 100 / cPAD, where cPAD for
adults and children = 0.03 mg/kg/day;   

c--children 1-2 years of age, adults 20-49 years of age

d--food processing plants for meats/fish have exposures which are
similar to other food contact surfaces, exposure numbers not included
for this scenario.

e-- includes all fruits and vegetables and apple and orange juices;
assumes 100% of fruit is washed with chlorine dioxide.

f--Infants (<1 year) are included in this table for comparison purposes
and were not added to the total dietary exposure as it was not the most
highly exposed subpopulation.

g--Assuming 50% of fruits/vegetables are treated, the dietary risk for
children (1 – 6) would represent 21% of the cPAD.

6.	Dietary Risk from Drinking Water

  XE "III. Summary of 2,4-DB Risk Assessments:5. Dietary (Food) Risk
Assessment: c. Dietary Risk from Drinking Water"  

Chronic dietary (water only) risk assessments were conducted using
DEEM-FCID™ Version 2.03 and drinking water consumption data from the
USDA’s CSFII from 1994-1996 and 1998.  Exposures were single point
estimates; no residue decline was utilized.

	Chlorine dioxide is commonly used as an antimicrobial material
preservative and for disinfecting non-porous surfaces indoors.  These
use patterns are not expected to result in surface or groundwater
contamination.  However, chlorine dioxide is commonly used for drinking
water treatment.  Therefore, the drinking water discussion will focus on
the dietary risks that result from drinking water treatment.

	In the U.S., there are two primary methods of drinking water treatment
that do not involve filtration.  The first method is the generation of
chlorine dioxide.  In the second method, either gaseous chlorine or
hypochlorite is used to produce free chlorine.  Except when gaseous
chlorine is used, these methods produce chlorate as a disinfection
byproduct (DBP).  The American Water Works Association (AWWA)
Disinfection Systems Committee tracks disinfection practices in US
community water systems.  AWWA’s most recent comprehensive survey
(completed in 1998) estimated that, of all community water systems
(CWS), approximately 20% of CWSs serving populations greater than 10,000
use sodium hypochlorite (2% generated it on-site), 8% use chlorine
dioxide, and <1% use calcium hypochlorite.  For CWSs using groundwater
and serving populations less than 10,000, the survey estimated that
approximately 34% use sodium hypochlorite, none use chlorine dioxide,
and at least 4.5% use calcium hypochlorite.  For CWSs using surface
water and serving less than 10,000, the survey estimated that 17% use
sodium hypochlorite, 6% use chlorine dioxide, and 9% use calcium
hypochlorite.

	For chlorine dioxide generation, both sodium chlorate and sodium
chlorite are used as precursor materials in the water disinfection
process.  Sodium chlorite is more commonly used than sodium chlorate. 
The free chlorine disinfection process involves the use of either
gaseous chlorine, or sodium or calcium hypochlorite, as precursor
materials.  Historically, gaseous chlorine has been far more widely used
than hypochlorite to produce free chlorine.  In recent years, primarily
as a result of various homeland security measures, many drinking water
systems are switching from gaseous chlorine to hypochlorite.  These
processes (except for the use of gaseous chlorine) result in chlorate
byproduct in finished drinking water, exposure to which was considered
in the Inorganic Chlorates RED. 

The chlorite ion (ClO2-) is a major degradation product resulting from
the reaction of chlorine dioxide with inorganic and organic constituents
in the water.  When free chlorine is used after the application of
chlorine dioxide in the treatment process, chlorite is oxidized to
chlorate.  This conversion will continue over time as the water travels
through the distribution system.  Chlorate ion is also formed by
photodecomposition of chlorine dioxide when treated water is exposed to
bright sunlight in open basins.  The rate at which chlorate forms
affects the amount of chlorine dioxide or chlorite that remain in the
finished drinking water.  Formation of chlorate from chlorite and
chlorine dioxide was considered in the Inorganic Chlorates RED. 

Drinking Water Exposure

Data on the occurrence of sodium chlorite in drinking water were
available from the Information Collection Rule (ICR) Auxiliary 1
Database, Version 5.0.  The water systems represented in the ICR
database serve 60% of the total U.S. population.  The EPA Office of
Water (OW) issued the ICR in order to collect data to support future
regulation of microbial contaminants, disinfectants, and disinfection
byproducts.  Monitoring for sodium chlorite was included in the ICR. 
Source water and drinking water were monitored for sodium chlorite ion
between July 1997 and December 1998.  Water systems serving a population
of at least 100,000 were required to monitor for chlorite ion at
treatment plants using chlorine dioxide or hypochlorite solutions in the
treatment process.  Plants using chlorine dioxide collected monthly
samples of the source water entering the plant, the finished water
leaving the plant, and at three sample points in the distribution system
(near the first customer, an average residence time, and a maximum
residence time).  Plants using hypochlorite solutions were required to
collect quarterly samples of the water entering and leaving the plant. 
If chlorine dioxide or hypochlorite solutions were used intermittently
at a plant, chlorite ion samples were only required in sample periods in
which they were in use.  

Monitoring data were collected from 29 water treatment plants using
chlorine dioxide treatment.  The minimum reporting level (MRL) was
established at 20 µg/L, all samples below this value were considered
zero.  Data from 418 samples (point of entry to the distribution) showed
chlorite ion concentration ranged from 20 µg/L to 2,029 µg/L. Data
from 1,115 samples (collected from within the distribution system)
showed the concentration of chlorite ion between 20 µg/L to 1,850
µg/L.  The average concentration of chlorite ion from 27 out of 29
treatment plants when averaged from the three distribution system sample
points ranged from 20µg/L to 801 µg/L.

Based on the results of this monitoring data, the Agency established a
maximum contaminant level goal (MCLG) and a maximum contaminant level
(MCL) for chlorite ions.  The MCLG and MCL are 0.8mg/L and 1.0 mg/L,
respectively.  In the original ICR monitoring data a number of samples
and distribution systems showed large exceedences based on the MCL and
MCLG.  Currently, water systems have indicated that treatment is
generally designed to meet a level of at least 20% below the MCL in
order to ensure compliance. Based on this assumption, the Agency has
readjusted all reported concentrations over 1000µg/L to 800 µg/L and
recalculated the data.  Table 4 below shows the adjusted values for
chlorite concentrations.

	Based on the values obtained from the monitoring data, the Agency
conducted a drinking water assessment using chlorite concentrations at
the maximum, 90th percentile, and median annual averages of chlorite
concentrations of 0.7, 0.63, and 0.39 mg/L, respectively.  The 90th
percentile exposure values will be used in the aggregate risk
assessments, with children represented by the 1-6 year old age category.
 

Table 4.  Chlorine Dioxide Water Monitoring Data (g/L) – ICR Dataa 


	Distribution System Entry Point	Near First Customer	Average Residence
Time	Maximum Residence Time	Distribution System Average2

10th Percentile	60	52	58	30	45

20th Percentile	99	79	87	81	84

50th Percentile	440	380	360	310	390

80th Percentile	590	580	600	510	550

90th Percentile	660	660	640	650	630

Maximum	800	740	680	680	700

Number of Water Treatment Plants	29	27	27	27	27

Number of Public Water Systems	22	21	21	21	21

	aICR Data Adjusted for MCL Compliance

			b.	Acute Dietary Risk (Drinking Water)

No acute dietary endpoint was selected because effects attributable to a
single dose were not seen in the available data; therefore, an acute
dietary risk assessment was not conducted.  

Chronic Dietary Risk (Drinking Water)

The chronic dietary (water only) risk assessment for sodium chlorite in
drinking water estimated at 49 % of the cPAD for the general U.S.
population and is below 100% of the cPAD, and therefore, is below the
Agency’s level of concern.  All risks for the U.S. population
subgroups are below 100 % of the cPAD except infants (<1 year of age). 
The highest exposed subgroup, infants, was 161% of the cPAD, based on
the highest annual average concentration of sodium chlorite, and
therefore, above the Agency’s level of concern.  The 90th percentile
exposure values will be used in the aggregate risk assessments, with
children represented by the 1-6 year old age category.  See Table 5
below for details.

Table 5. Chlorite Exposure by Population Group

Population subgroup	Maximum Concentration	90th Percentile Concentration
Median Concentration

	Total exposure

(mg/kg/day)	% cPAD	Total exposure

(mg/kg/day)	% cPAD	Total exposure (mg/kg/day)	% cPAD

U.S. Population	0.014754	49	0.013279	  44	0.008220	27

Infants < 1 year	0.048372	161	0.043535	145	0.026950	90

Children 1-6 years	0.020613	69	0.018552	  62	0.011485	38

Children 7 -12 years	0.013402	45	0.012062	  40	0.007467	25

Females 13-50	0.014274	48	0.012846	  43	0.007952	27



Residential Exposure 

Residential exposure assessment considers all potential pesticide
exposure, other than exposure due to residues in food or in drinking
water.  Residential exposure may occur during cleaning or mopping of
hard surfaces, application of chlorine dioxide to swimming pools and
spas and through application to HVAC systems.  Each route of exposure
(oral, dermal, inhalation) is assessed, where appropriate, and risk is
expressed as a Margin of Exposure (MOE), which is the ratio of estimated
exposure to an appropriate NOAEL.  Based on its use pattern, the
residential handler assessment evaluated application of chlorine
dioxide-containing products by homeowners to control mold and mildew. 
The post-application assessment evaluated risks from dermal, inhalation
and incidental oral exposure for children due to hand-to-mouth exchange.
 

Toxicity

The toxicological endpoints and associated uncertainty factors used for
assessing the non-dietary risks for chlorine dioxide and sodium chlorite
are listed in Table 6.

A MOE greater than or equal to 100 is considered adequately protective
for the residential exposure assessment for the dermal, incidental oral
and inhalation routes of exposure. The MOE of 100 includes 10x for
inter-species extrapolation, 10x for intra-species variation. 



Table 6.  Summary of Toxicological Doses and Endpoint Selection for the

Chlorine Dioxide/ Sodium Chlorite Residential Assessment

Exposure Scenario	Dose Used in Risk Assessment (mg/kg/day)	UF/MOE for
Risk Assessment	Study and Toxicological Effects

Incidental Oral

(short and intermediate term)	NOAEL = 3 mg/kg/day	MOE  = 100
Two-generation reproduction toxicity study (CMA, 1996) - decreases in
absolute brain and liver weight, and lowered auditory startle amplitude
at LOAEL of 6 mg/kg/day

Developmental Toxicity - Rat (Orme et al., 1985)- neurobehavioral and
exploratory deficits in rat pups at LOAEL of 14 mg/kg/day

Dermal

All Durations (1-30 days)	NOAEL = 3 mg/kg/day	MOE = 100	Two-generation
reproduction toxicity study (CMA, 1996) - decreases in absolute brain
and liver weight, and lowered auditory startle amplitude at LOAEL of 6
mg/kg/day

Developmental Toxicity - Rat (Orme et al., 1985)- neurobehavioral and
exploratory deficits in rat pups at LOAEL of 14 mg/kg/day

Inhalation

(occupational and homeowner short-term)	Homeowner 

short-term: 

LOAEL = 28 mg/m3 (10 ppm)

Occupational exposure: 

LOAEL  = 2.8 mg/m3 (1.0 ppm)

NOAEL = 0.28 mg/m3 (0.1 ppm).	Homeowner short-term ‘RfC’ = 0.14
mg/m3 (0.05 ppm)

Occupational ‘RfC’ = 0.009 mg/m3 (0.003 ppm)	Inhalation toxicity
studies- Rat

Dalhamn, 1957; Paulet and Debrousses, 1970, 1972.

Inhalation (homeowner long-term)	Agency RfC methodology used to derive
an RfC value of 2 x 10-4 mg/m3 (USEPA, 2000a)	(Paulet and Desbrousses,
1970, 1972) selected as co-critical studies (USEPA, 2000a)



Residential Handler

Exposure Scenarios, Data and Assumptions

Residential exposure to chlorine dioxide can occur through mopping,
spraying, and applying products to pools and spas.  A number of
assumptions, or estimates, such as adult body weight and area treated
per application, are made by the Agency for residential risk assessment.
 Also, note that residential handlers are addressed somewhat differently
than occupational handlers in that homeowners are assumed to complete
all elements of an application (mix/load/apply) without the use of
personal protective equipment.  In addition, for residential handlers it
is assumed that all exposures are short-term.

The residential handler risk assessment based on these scenarios:

	(1)	Mopping: 1 gal/use

	(2)	Trigger-pump sprayers: 0.5 liters or 0.13 gal/day

	(3)	Swimming pools:  160 g ai/20,000 gallons of water

Chlorine dioxide and sodium chlorite products are widely used and have a
large number of use patterns that are difficult to completely capture in
the risk assessment.  As such, the Agency has selected representative
scenarios for each use site that are believed to be high-end estimates
for the vast majority of chlorine dioxide uses, based on end-use product
application methods and use amounts.

For the residential handler risk assessment, dermal unit exposure values
were taken from the proprietary Chemical Manufacturers Association (CMA)
antimicrobial exposure study, 1999, (MRID 42587501) or from the
Pesticide Handler Exposure Database (PHED, 1998).  The scenarios
evaluated for dermal and inhalation risks in the residential handler
assessment are as listed below:

Mopping floors;

Applying trigger-pump sprays to hard surfaces; and 

Placing solid tablets in swimming pools or spas

Off-gassing during application of the aqueous solution.  

The potential exposures from mopping and cleaning are expected to be
best represented by the short-term duration.  Dermal and inhalation
exposures were assessed for all residential handler scenarios.  For the
mopping application and application of tablets to swimming pools and
spas, values from the Chemical Manufacturers Association (CMA)
antimicrobial study (U.S. EPA, 1999) were used.  For the application of
chlorine dioxide products with a trigger-pump spray, the Pesticide
Handler Exposure Database (PHED, 1998) was used to determine exposure.  


To determine the potential inhalation handler exposure resulting from
the vapor of chlorine dioxide as a general purpose cleaner, the model
EFAST (Exposure and Fate Assessment Screening Tool) was used to estimate
the chlorine dioxide air concentrations.  For additional information,
please refer to “Chlorine Dioxide Occupational and Residential
Exposure Assessment,” dated August 2, 2006.

Residential Handler Risk Estimates

Based on toxicological criteria and potential for exposure, the Agency
has conducted dermal and inhalation exposure assessments.  A summary of
the residential handler exposures and risk are presented on Table 7. 
The exposure duration of most homeowner applications of cleaning
products and pools are believed to be best represented by the short-term
duration.  The toxicological endpoint is based on an oral study and no
dermal absorption value is available.  Therefore 100% dermal absorption
was assumed for chlorine dioxide or chlorite ion residues.  While there
is some evidence that chlorine dioxide is readily absorbed in skin, this
assessment is very conservative.  The dermal MOEs for the floor mopping,
and application to hard surfaces, are above the target MOE of 100, and
therefore, are not of concern.  The short-term dermal MOE for pool or
spa treatments is 46 without the use of gloves and is of concern to the
Agency; therefore, the labels must be amended to require gloves.  Based
on the average daily air concentration, the handler inhalation exposures
of chlorine dioxide are not of concern (i.e., the average air
concentration estimated by EFAST of 0.003 ppm is below the RfC of 0.05
ppm).  

Table 7. Calculation of Short-term Dermal MOEs for Residential Handlers

Exposure Scenario	Application Ratea

(lb ai/gal)	Amount Handled/ Treated Dailyb

(gal)	Baseline Dermal Unit Exposurec (mg/lb ai)	Baseline Dermal Dosed,e 

(mg/kg/day)	Baseline Dermal MOEf 

(Target MOE = 100)

Mopping

(CMA data)	Hard Surfaces	0.002	1	71.6	0.0024	1300

Trigger-pump sprayer (Aerosol can

PHED data used as surrogate)	Hard Surfaces	0.002	0.13	220	0.00095	3200

Solid Place 

(Tablets)

	Pools & Spa water Circulation Systems	1.8E-5

(4 tablets /10,000 gal.  Pool tablet is 100 g x 4 tablets x 20%ai = 80 g
ai/10,000 gal = 1.8E-5 lb ai/gal)	20,000 gal	10.8

(no gloves)	0.065

(no gloves)	46

(no gloves)





0.412

(with gloves)	0.006

(with gloves)	500

(with gloves)



Residential Post-Application

Exposure Scenarios, Data and Assumptions

Residential post-application exposures result when bystanders (adults
and children) come in contact with chlorine dioxide in areas where
pesticide end-use products have recently been applied (e.g., treated
hard surfaces/floors), or when children incidentally ingest the
pesticide residues through hand-to-mouth contact of the treated surface.
The residential post-application scenarios considered in this assessment
are exposure to residues from hard surfaces (i.e., floors) that have
been mopped or cleaned with a product containing chlorine dioxide, the
use of continuous release air deodorizers, and a single treatment of
HVAC systems with chlorine dioxide.

	Chlorine dioxide and/or sodium chlorite can be applied as an aqueous
solution to hard surfaces such as floors and potentially result in
inhalation exposure.  The Agency assessed these risks based on dilution
and ventilation along with the half-life of chlorine dioxide.  This
assessment estimated an 8-hour time weighted average air concentration
starting immediately after application.

	Typically, most products used in a residential setting result in
exposures occurring over short-term time duration (1 – 30 days).  For
the purposes of this screening-level assessment, post application
scenarios have been developed that encompass multiple products, but
still represent a high-end scenario for all products represented.  

Four scenarios have been evaluated in the residential post-application
assessment.

Exposure to residue from hard floors that have been cleaned with a
solution containing chlorine dioxide;

Exposure to chlorine dioxide used to clean residential HVAC systems;

Exposure to a continuous release (gas) deodorizer; and 

Swimming in treated pools or spas. 

Residential Post-Application Risk Estimates

Based on toxicological criteria and potential for exposure, the Agency
has conducted dermal, incidental oral and inhalation exposure
assessments.  As noted previously, MOEs greater than or equal to 100 are
considered adequately protective for the residential exposure
assessment.  

  SEQ CHAPTER \h \r 1  A summary of the residential handler exposures
and risk are presented on Table 8. The risks from dermal and incidental
oral exposures for all scenarios are below the Agency’s level of
concern. 

	  SEQ CHAPTER \h \r 1 For children, the short- and intermediate-term
oral and dermal MOEs for contact of hard surfaces following disinfection
are above the target MOE of 100 for applications in residential and
daycare settings.  Therefore, the risks from these uses are not of
concern.  

	Inhalation exposures due to post application activities could occur for
children after the treatment of floors; adults and children after the
treatment of HVAC systems; and adults and children after the use of
continuous release (gas) deodorizers.  Chlorine dioxide/sodium chlorite
can be applied as an aqueous solution to hard surfaces such as floors
and potentially result in inhalation exposure.  For this assessment, the
Agency estimated the air concentration to be 0.003 ppm, which is below
the short-term RfC of 0.05 ppm, and therefore not of concern.  For
application to HVAC systems, this use is not of concern.  For the
continuous release deodorizer, the estimated constant air concentration
was 0.52 ppm, assuming no air exchange and no build up of chlorine
dioxide over time because of the short half-life.  This risk is of
concern to the Agency.  The RfC for long-term continuous exposure is
0.00007 ppm; therefore this risk is of concern to the Agency.  The
registrant has agreed to delete residential uses of these products.   

	The application of chlorine dioxide to swimming pools or spas, is not
assessed quantitatively.  Based on use directions on current labels,
dermal, incidental oral, and inhalation exposures to chlorine dioxide
residual levels after the dilution in the water, and cleaning of the
circulation systems are expected to be minimal.  Table 8 shows a
representative sample of the short- and intermediate-term residential
post-application risks.

	There is also the potential for inhalation exposure as a result of the
use of chlorine dioxide as a dust on carpets.  The registrant has agreed
to mitigate any potential risk from this use by limiting it to
professional carpet applicators, packaging only in containers that are
large enough to discourage retail sale and requiring an REI of one hour
prior to entry into a treated room. 

   

Table 8.  Summary of Short- and Intermediate-Term

Residential Post-application Exposures and Risks

Scenario	Dose a

(mg/kg/day) 	MOEb 

Dermal Exposure

Hard surface Disinfection	Residential Setting and

Daycare Center	0.017 a	280

Incidental Oral Exposure

Hard surface Disinfection	Residential Setting and

Daycare Center	0.0013a	2,300



Inhalation Exposure

Scenario	Estimated Air Concentration	RfC (level of concern)

Application to 

HVAC Systems	Residential Setting and

Daycare Center	<0.01 ppm	0.05 ppm c

Continuous Release Deodorizer	Residential Setting and

Daycare Center	<0.52 ppm	0.00007 ppm d

a	Dose calculations for each scenario above are outlined in the attached
Occupational/Residential Assessment.

b	MOE= NOAEL (mg/kg/day) / Dose (mg/kg/day). Oral and dermal NOAEL is 3
mg/kg/day.

c RfC  - short-term target is 0.05 ppm.

d RfC  - long-term target is  0.00007 ppm.

8.	Aggregate Risk  XE "III. Summary of 2,4-DB Risk Assessments:A. Human
Health Risk Assessment: 5. Dietary (Food) Risk Assessment"  

The FQPA amendments to the Federal Food, Drug, and Cosmetic Act (FFDCA,
Section 408(b)(2)(A)(ii)) require “that there is a reasonable
certainty that no harm will result from aggregate exposure to the
pesticide chemical residue, including all anticipated dietary exposures
and other exposures for which there is reliable information.” 
Aggregate exposure will typically include exposures from food, drinking
water, residential uses of a pesticide, and other non-occupational
sources of exposure.  

	In accordance with FQPA, the Agency must consider and aggregate
pesticide exposures and risks from three major sources: food, drinking
water, and if applicable, residential or other non-occupational
exposures.  In an aggregate assessment, exposures from relevant sources
are added together and compared to quantitative estimates of hazard
(e.g., a NOAEL), or the risks themselves can be aggregated.  When
aggregating exposures and risks from various sources, the Agency
considers both the route and duration of exposure.  Aggregate exposure
and risk assessments for sodium chlorite include the following: food +
water + residential handler.  For the aggregate of the inhalation route
of exposure, only use of the continuous release air deodorizer product
is assumed to co-occur with the other uses.  In addition, the HVAC
applications will not occur frequently (single exposure); therefore it
was not included in the aggregate assessment.  The inhalation risk for
the continuous release is of concern by itself.  Because we have
agreement that the residential application of the continuous release
deodorizer will be canceled, it has been removed from consideration in
the aggregate assessment.  However, the continuous release air
deodorizer will be allowed in spaces where extended exposure is not
likely, e.g., dumpsters.  This mitigation will result in aggregate risks
that are no longer a concern.  Results of the aggregate risk assessment
are summarized here, and are discussed more extensively in the document:
 Revised Chlorine Dioxide Risk Assessment, dated July 27, 2006, which is
available in the public docket.

Acute Aggregate Risk

	For chlorine dioxide, the acute and chronic aggregate risk assessments
include only dietary, drinking water, and residential exposures.  An
acute dietary risk assessment was not conducted for chlorine dioxide
because there were no acute dietary endpoints of concern.  

 		

Short- and Intermediate -Term Aggregate Risk

	The short- and intermediate-term aggregate assessments were conducted
for adults and children.  Table 9 shows the exposure scenarios that were
included in the aggregate assessment for chlorine dioxide.  Use patterns
involving exposure by inhalation (continuous use deodorizer) were not
aggregated because these use patterns were above the Agency’s level of
concern on their own and the Agency has agreement that the use will be
voluntarily cancelled, therefore these aggregate risks are no longer a
concern.

Table 9. Exposure Scenarios Included in the Aggregate Assessments

	Short-term Aggregate	Intermediate-Term Aggregate

Adults	chronic dietary (direct and indirect)

handling cleaning products – spray (dermal only)

handling cleaning products – mopping (dermal only)

chronic drinking water	Not Assessed

Children	chronic dietary – (direct and indirect)

post-app to cleaning product (dermal and oral)

chronic drinking water	chronic dietary – (direct and indirect)

post application to cleaning product (dermal and oral)

chronic drinking water

a Dietary (indirect + direct food contact) exposures = sum of dietary
exposures presented in Table 3.

b Aggregate Dietary Exposures = sum of both dietary (direct and indirect
food contact) exposures and drinking water exposures. 

	The toxicity endpoints for the oral and dermal routes of exposure are
based on the same study and same toxic effect; therefore, these two
routes of exposure are aggregated together.  Table 10 presents a summary
of these exposures, including the aggregate dietary exposure (all direct
and indirect food contact exposures) as well as a total dietary
aggregate exposure value (drinking water plus direct/indirect dietary
exposures).  Table 10 presents a summary of the short- and
intermediate-term aggregate exposures and the corresponding aggregate
risks. 

	The short-term and immediate-term aggregate risks are not of concern
for adults (total MOE=130).   The short-term and immediate-term
aggregate risks are of concern for children (MOE=44) and infants
(MOE=41).  The primary driver for these risks is dietary exposures.     


Table 10. Short- and Intermediate-term Aggregate Risks (MOEs)

Exposure Routes	Aggregate Dietary Risks	Dermal Risks (MOE)	Aggregate
Risks

(MOE)



Hard Surface Cleaning



	Applicator	Post-Application



	Mop	Spray



Adults

Oral Ingestion MOEs	150	NA	NA	NA	150

Dermal MOEs	NA	1300	3200	NA	900

Total MOE	150	1300	3200	NA	130

Children (age 1 – 6)

Oral Ingestion MOEs	60	NA	NA	2300	58

Dermal MOEs	NA	NA	NA	180	180

Total MOE	60	NA	NA	160	44

Infants < 1

Oral Ingestion	55	NA	NA	2300	55

Dermal MOEs	NA	NA	NA	180	180

Total MOE	55	NA	NA	160	41

MOE = NOAEL/dose

Aggregate MOE = 1/((1/MOEdietary) + (1/MOEdrinking water) +
(1/MOEdermal)

All NOAELs = 3 mg/kg/day

Target MOE oral = 100

Target MOE dermal = 100

Chronic Aggregate Risk

	The chronic aggregate risk estimates associated with chlorine dioxide
from dietary uses are below the Agency’s level of concern for adults
at 53% of the cPAD.  However the dietary risks are above the level of
concern for children aged 1 to 6 (133% of the cPAD).

	The chronic aggregate risks are not of concern for adults, as the total
aggregate of the cPAD is 53% (excluding the continuous use deodorizer),
below the target of 100%.  For children, the aggregate risk estimates
are above 100% (133% cPAD) and thus are of concern.  Table 11 presents
the chronic aggregate exposures and risks.  



Table 11.  Chlorine Dioxide Chronic Aggregate Exposures and Risks

Exposure Routes	Chronic Dietary Exposures (mg/kg/day)

	Dietary (indirect + direct food contact+ chlorate) Exposuresa	Drinking
water exposures 	Aggregate Dietary Exposuresb	Aggregate Dietary Risks
(%cPAD)

Adults

Oral Ingestion	2.65E-03	1.33E-02	1.6E-02	53.3%

Children (age 1 – 6)

Oral Ingestion	2.27E-02	1.86E-02	4.13e-02	133%

a Dietary (indirect + direct food contact) exposures = sum of dietary
exposures presented in Table 6.

b Aggregate Dietary Exposures = sum of both dietary (direct and indirect
food contact) exposures and drinking water exposures.  

		9.	Occupational Exposure and Risk 

Workers can be exposed to a pesticide through mixing, loading, and/or
applying a pesticide, or re-entering treated sites.  Occupational
handlers of chlorine dioxide and sodium chlorite include workers in a
variety of occupational settings.  Additionally, post-application
exposures are likely to occur in these settings.  The representative
scenarios selected for assessment were evaluated using maximum
application rates as recommended on the product labels for chlorine
dioxide and sodium chlorite. 

Occupational risk is assessed for exposure at the time of application
(termed “handler” exposure) and is assessed for exposure following
application, or post-application exposure.  Application parameters are
generally defined by the physical nature of the formulation (e.g.,
formula and packaging), by the equipment required to deliver the
chemical to the use site, and by the application rate required to
achieve an efficacious dose.   

Occupational risk for all of these potentially exposed populations is
measured by a Margin of Exposure (MOE), which determines how close the
occupational exposure comes to a No Observed Adverse Effect Level
(NOAEL) from toxicological studies.  In the case of chlorine dioxide and
sodium chlorite, MOEs greater than 100 for dermal exposures and
inhalation exposures are not of concern to the Agency.  For workers
entering a treated site, MOEs are calculated for each day after
application to determine the minimum length of time required before
workers can safely re-enter.

For more information on the assumptions and calculations of potential
risk of chlorine dioxide to workers, see the Occupational Exposure
Assessment section in the “Chlorine Dioxide Risk Assessment,” dated
July 27, 2006. 

a.  	Occupational Toxicity   XE "III. Summary of 2,4-DB Risk
Assessments:7. Occupational Risk:a. Occupational Toxicity"  

	Table 6 provides a listing of the toxicological endpoints used in the
occupational risk assessment for chlorine dioxide and sodium chlorite.

Occupational Handler Exposure 

  XE "III. Summary of 2,4-DB Risk Assessments:7. Occupational Risk:b.
Occupational Handler Exposure"  

Potential occupational handler exposure can occur at various use sites,
including agricultural, food handling, commercial and institutional, and
medical premises; human drinking water systems; industrial processes and
water systems; application to materials as preservatives; and swimming
pools and other aquatic areas.  

	

The Agency has assessed the handler risks from the use of chlorine
dioxide using unit exposure data from both the proprietary Chemical
Manufacturers Association (CMA) antimicrobial exposure study and the
Pesticide Handlers Exposure Database (PHED). Table 12 lists the handler
exposure scenarios assessed for chlorine dioxide.  These scenarios are
considered representative of high-end exposures for the industrial
applications. 

Table 12. Exposure Scenarios Associated with 

Occupational Exposure Assessed in this Document

Representative Use	Application Method	EPA Registration Number (chemical
associated with use)	Application Rate (lb ai/gal)	Exposure Scenario
Assessed

Use Site Category I (Agricultural Premises and Equipment)a

Application to Hard Surfaces and Equipment	low-pressure hand wand
74602-2 

(Sodium Chlorite)	(Application rate from label, 2.5 fl oz/gal)*(1
gal/128 oz)*(0.75 lb ai/gal) = 0.015	Short- and Intermediate-term (ST
and IT) Adult Handler (dermal and inhalation) and Adult Bystander and
Post Application (dermal and inhalation)



	trigger-pump sprayer

fogger (1 hour REI after fogging)	74602-2 

(Sodium Chlorite)	(Application rate from label, 2.5 fl oz/gal)*(1
gal/128 oz)*(0.75 lb ai/gal) = 0.015



mop	9150-2

(Chlorine Dioxide)	(Application rate from label, 3.25 fl oz/gal)*(1
gal/128 oz)*(0.69 lb ai/gal) = 0.018



foaming wand	9150-11

(Chlorine Dioxide)	(Application rate from label, 0.25 gal of
product*0.10 lb ai/gal) = 0.025 lb ai/gal.)  Apply at rate of 4 to 6
gallons/minute to inside/outside of animal trucks/equipment.



ULV fogger (e.g., Dramm fogger)	74602-2

(Sodium Chlorite)	( Egg house label rate, 1 gal product x 5% ClO2) per
50 gal = 0.0083)

	Use Site Categories II (Food Handling), III (Commercial/Institutional),
and V (Medical)

Application to Hard Surfaces and Equipment Without Food Contact

	mop 	9150-10 active

(10589-3 transferred)

(Chlorine Dioxide)	(Application rate from label, 5 oz/gal)*(1 gal/128
oz)*(0.49 lb ai/gal) = 0.019	ST/IT Adult Handler (dermal and inhalation)
and Adult Post Application/Bystander (dermal and inhalation)

	trigger-pump sprayer	21164-3

(Sodium Chlorite)

	(Application rate from label, 12 fl oz/gal)*(1 gal/128 oz)*(0.86 lb
ai/gal) = 0.08

	Application to foods (Fruit/Vegetable Rinse) 	dip	74602-2

(Sodium Chlorite)	(Application rate from label, 1.9 oz/gal)*(1 gal/128
oz)*(0.75 lb ai/gal) = 0.011

	Use Site Category VI (Human Drinking Water Systems)

Application to Water Systems (Water Treatment and Water Storage Systems)
metering pump	9804-1

(Chlorine Dioxide)

	(Application rate from label, 3.25 fl oz/gal)*(1 gal/128 oz)*(0.27 lb
ai/gal) = 0.007	ST/IT Adult Handler; Potential for inhalation exposure
unknown at this time.

Use Site Category VII (Material Preservatives)

Applications to Metal Working Fluids	liquid pour	9150-2

(Chlorine Dioxide)	batch method: 0.0001 

(per week)

continuous method: 

8E-7 (per day)

badly contaminated systems:  4E-6 (slug dose)	ST/IT Adult Handler
(dermal and inhalation) and Long-term Dermal and Inhalation for
Machinists.

Use Site Category VIII (Industrial Processes and Water Systems)

Application to Pulp and Paper White Water Systems	metering pump	74602-3

(Sodium Chlorite)

	(Application rate from label, 15 gal/100,000 gal white water to be
treated or 4 gal/100 tons paper produced)*(0.86 lb ai/gal) = 0.0001 lb
ai/gal white water or 3.44 lb ai/100 ton paper produced	ST/IT Adult
Handler (dermal and inhalation) and Adult Bystander (inhalation)

Application to Oil Systems (oil Wells During Secondary 

Recovery Operations)

	liquid pour	9150-2

(Chlorine Dioxide)

	(Application rate from label, 1 gal/10 gal)*(0.69 lb ai/gal) = 0.069.

Label indicates to portion 1 part of this solution to 150 parts
reinjection water.	ST/IT Adult Handler (dermal and inhalation) and Adult
Bystander (inhalation)

Use Site Category XI (Swimming Pools)

Application to Public Swimming Pool Circulation Water Systems (Swimming
Pools)	solid place (tablets)	70060-20

(Sodium chlorite)

	4 tablet /10,000 gal 

(Pool tablet is 100 g x 4 tablets x 20%ai = 80 g ai/10,000 gal = 1.8E-5
lb ai/gal)	Short-term Adult Handler (dermal and inhalation)

Use Site Category XII ( Aquatic Areas)

Non-potable Water Systems (e.g., retention basins and ponds, decorative
pools and fountains)	liquid pour	9150-11

(Chlorine Dioxide)	0.00001

(18 fl oz x 0.72% ai per 100 gallons water)	ST/IT Adult Handler (dermal
and inhalation)

Use Site Category XIII (HVAC)

Application to Ventilation Systems

(HVAC)	airless sprayer

fogger  (1hour REI after fogging)	9804-1

(Chlorine Dioxide)	(Application rate from label, 3.25 fl oz/gal)*(1
gal/128 oz)*(0.27 lb ai/gal) = 0.007	ST/IT Adult Handler (dermal and
inhalation) and Short-term Child and Adult Post Application (inhalation)



Occupational Handler Risk Summary

i. 	Dermal Risks

For the occupational handler dermal risk assessment, the short- and
intermediate- term risks calculated at baseline exposure (no gloves and
no respirators) were above target MOEs for all scenarios (i.e., dermal
MOEs were >100), except for the following: 

Agricultural premises and equipment:

application to hard surfaces: low pressure handwand (MOE=31);

application to hard surfaces: mopping (MOE=70); and

application to hard surfaces: foam applicator equipment (MOE=8). 

Food Handling, Commercial/Institutional, and Medical Premises and
Equipment:

application to hard surfaces: 

mopping (MOE=66 commercial; 3 medical).

Swimming pools:  

placement of tablets (MOE=5)

	

A summary of the occupational handler assessment is provided in Table
13.



Table 13.  Short-, Intermediate-Term Dermal Risks for Occupational
Handlers

Exposure Scenario	Method of Application	Application Rate  

(lb ai/ gallon)	Quantity Handled/

Treated per day (gallons)	Dermal MOEc





Baseline Dermala

(Target MOE>100)	PPE Gloves Dermalb

(Target MOE>100)

1Agricultural Premises and Equipment

Application to Hard Surfaces	Low pressure handwand	0.015	2	31	No data

	Liquid Pour

0.188	1,300	6,300

	Trigger-pump sprayer

0.26	240	570

	Mopping	0.018	2	70	No data

	Foam applicator equipment	0.025 	60	3	8

Food Handling, Commercial/Institutional, and Medical Premises and
Equipment

Application to Hard Surfaces	Mopping (general)	0.019	2	66	No data

	Trigger-pump sprayer	0.08	0.26	46	110

	Mopping

(medical)	0.019	45	3	No data

Human Drinking Water Systems

Water and Storage Systems	Metering pump	0.007	34,000	No data	120

Material Preservatives

Metal Working Fluid	Liquid pour	0.0001	300	No data	33,000

Industrial Processes and Water Systems

Paper and Pulp White Water Systems	Metering pump	0.0344 lb ai/ton paper
500 tons paper	No data	2,300

Oil Systems	Open pour	0.069	2.8	NA	6,900



	5.6

3,500

Swimming Pools and Aquatic Areas

Retention Ponds/ Fountain	Liquid pour	0.00001	10,000 gal	No data	670

Swimming Pools (public)	Solid place	1.8E-5	200,000 gal	5	120

HVAC Systems

HVAC	Airless sprayer	0.007	5	140	NA

	Fogger 

(liquid pour)

0.25	2,000	NA

a	Baseline Dermal:  Long-sleeve shirt, long pants, no gloves.

b	PPE Dermal with gloves: baseline dermal plus chemical-resistant
gloves.

c	MOE = NOAEL  (mg/kg/day) / Daily Dose [Where short-and
intermediate-term NOAEL = 3 mg/kg/day for dermal exposure]. Target MOE
is 100 for dermal exposure.

	

			ii.	Inhalation Risks

Inhalation exposures and risks were not assessed separately for the
handlers.  Instead, the occupational inhalation handler exposures are
combined as part of the full work-day for handler/bystanders to be
comparable to EPA’s inhalation toxicological endpoint which is based
on an 8-hour time-weighted average.  For the peak, short-term exposures
to chlorine dioxide gas experienced during mixing/loading and/or system
leaks/failures, EPA will rely on the American Conference of Governmental
Industrial Hygienists (ACGIH) Short-term Exposure Limit (STEL) and
Immediately Dangerous to Life or Health (IDLH) standards to mitigate
risks.  

For most of the bystander/post application occupational scenarios, the
inhalation risks for the bystander/post application occupational
exposures are of concern using the EPA’s selected inhalation
toxicological endpoint (RfC).  The occupational RfC, 0.003 ppm, is below
the limit of detection for chlorine dioxide.  Based on OSHA’s
Integrated Management Information System (IMIS) data available for
chlorine dioxide, all air concentration measurements, even those that
were undetectable, are above the RfC.  EPA is aware of the discrepancy
between the EPA risk-based RfC and current OSHA standards,
reconciliation will occur at a later date.  

d.	Occupational Post-application

					i.	Dermal Post-Application Exposure

	

	No information is available to assess post application/bystander dermal
exposure to uses in agricultural premises as well as food handling,
commercial/institutional and medical premises; human drinking water
facilities; industrial processes; and retention ponds.  However, dermal
post application exposure to chlorine dioxide is expected to be less
than that of the dermal contact of children playing on treated floor
surfaces.  Therefore, the dermal exposure route is not believed to be of
concern in these industries.  

					ii.	Inhalation Post-Application Exposure

Non-Fogging Uses

Post-application/bystander inhalation exposures were assessed by
obtaining air concentration measurements from the Occupational Safety
and Health Administration (OSHA) for the non-fogging uses. The data
selected for this analysis include only those samples that are reported
as 8-hour time-weighted average (TWA) measurements from personal air
samplers.  Other samples, such as peak concentrations and/or area
monitors, have been omitted.  The inhalation endpoint selected by EPA is
0.003 ppm, just below the OSHA LOD for an 8-hour TWA air sample.  The
summary results of the 33 observations taken from 8-hour TWA personal
air samplers for chlorine dioxide are above the EPA selected inhalation
reference concentration (RfC) of 0.003 ppm, and therefore, are of
concern. 

Fogging Uses

The fogging use of chlorine dioxide is unique such that no persons are
present during the actual application/fogging.  There is also a greater
potential for chlorine dioxide gas formation from fogging than an
aqueous-based application such as mopping.  Therefore, a separate
assessment was developed for foggers that indicate potential inhalation
exposure and reentry recommendations.  The air concentration in a fogged
area should be below the occupational RfC of 0.003 ppm before the room
is entered by persons not wearing respiratory protection.  

One scenario based on labeled application rates allows chlorine dioxide
fogging and misting applications while workers are in the room if the
level of chlorine dioxide does not exceed the TLV-TWA of 0.1 ppm.  The
occupational RfC of 0.003 ppm could be exceeded based on these use
directions (i.e., workers do not need to leave treatment area unless the
TLV-TWA of 0.1 ppm is exceeded).  This scenario is of potential concern
to the Agency.  To mitigate this risk, labels must be changed to
prohibit re-entry into treated areas for one hour after treatment.

EPA’s Risk-based RfC versus OSHA PEL

		

It is also important to note that the OSHA Permissible Exposure Limit
(PEL) for chlorine dioxide is 0.1 ppm.  Air concentrations above the PEL
are assumed to be mitigated at each facility.  Facilities using chlorine
dioxide are not required to mitigate inhalation exposures until the air
concentration reaches 0.1 ppm.  Based on the occupational inhalation
toxicological endpoint selected for chlorine dioxide (i.e., RfC of 0.003
ppm), levels at or near the PEL are of concern.  In fact, the capability
(i.e., LOD) of the OSHA sampling method is insufficient for the
occupational RfC presented in this document.  Reconciliation of the EPA
risk-based RfC and the current OSHA standards will be made at a later
date.		

					e.  	Human Incident Data   XE "III. Summary of 2,4-DB Risk
Assessments:7. Occupational Risk:e. Human Incident Data"  

  XE "III. Summary of 2,4-DB Risk Assessments:7. Occupational Risk:e.
Human Incident Data"  

The Agency reviewed available sources of human incident data for
incidents relevant to chlorine dioxide/sodium chlorite.    tc "8.0
INCIDENTS"   SEQ CHAPTER \h \r 1 EPA consulted the following sources of
information for human poisoning incidents related to TCMTB use:  (1) OPP
Incident Data System (IDS) - The Office of Pesticide Programs (OPP)
Incident Data System contains reports of incidents from various sources,
including registrants, other federal and state health and environmental
agencies and individual consumers, submitted to OPP since 1992;  (2)  
SEQ CHAPTER \h \r 1 California Department of Pesticide Regulation
(1982-2004) – The California Department of Pesticide Regulation
pesticide poisoning surveillance program consists of reports from
physicians of  illness suspected of being related to pesticide exposure
since 1982.  (3)   SEQ CHAPTER \h \r 1 National Pesticide Information
Center (NPIC) - NPIC is a toll-free information service supported by OPP
that provides a ranking of the top 200 active ingredients for which
telephone calls were received during calendar years 1984-1991.

There are some reported incidents associated with exposure to end-use
products containing chlorine dioxide.  Inhalation is the primary route
of exposure.  Most of the incidents are related to irritation type
reactions to bronchial and nasal passages, and the eyes.  

The most common symptoms reported for cases of inhalation exposure were
respiratory irritation/burning, irritation to mouth/throat/nose,
coughing/choking, shortness of breath, dizziness, flu-like symptoms, and
headache.  

B.  	Environmental Risk Assessment   XE "III. Summary of 2,4-DB Risk
Assessments:B. Environmental Risk Assessment"  

A summary of the Agency’s environmental risk assessment is presented
below.  The following risk characterization is intended to describe the
magnitude of the estimated environmental risks for chlorine dioxide and
sodium chlorite use sites and any associated uncertainties.

For a detailed discussion of all aspects of the environmental risk
assessment, see the document “Environmental Hazard and Risk
Assessment,” dated July 13, 2006. 

Environmental Fate and Transport

In the environment, chlorine dioxide and sodium chlorite are assessed
together because chlorine dioxide is produced by a reaction of sodium
chlorite (and sometime sodium chlorate) and hypochlorite/acid. In
addition, chlorite is a breakdown product of chlorine dioxide.  

Chlorine dioxide has a short half-life and in the presence of sunlight
will break down into chloride and chlorate ions (between pH 4 and 7). 
At pH lower than 4, its breakdown products are chlorite and chlorate.
Chlorite is the dominant breakdown product.  

Chlorate and chlorite ions tend to only undergo biodegradation only
under anaerobic conditions.  Biodegradation of chlorate and chlorite has
been observed in anoxic groundwater, sediments and some soils. The end
products are the chloride and oxygen.  No adsorption/desorption
constants (Kds) have been measured or reported in published literature
for either chlorite or chlorate.  These ions are likely to be mobile and
may travel from surface to groundwater easily.  The estimated log Kow of
chlorine dioxide is -3.22 and for sodium chlorite is -7.17.  It is not
expected that either would bioaccumulate in aquatic organisms.  

Ecological Exposure and Risk  

Chlorine dioxide and sodium chlorite are used as antimicrobial
pesticides at numerous use sites.  Sodium chlorite is used as a
precursor in the generation of chlorine dioxide.  The antimicrobial
registered uses of chlorine dioxide/sodium chlorite fall into several
major categories including use in the treatment of human drinking water
systems; in industrial process and water systems; as a materials
preservative; and as a general disinfectant in medical, residential,
agricultural, commercial and industrial settings.  The indoor uses of
sodium chlorite will not result in exposure to the environment. 

 

The use of chlorine dioxide in cooling towers was modeled because it
represents the worst-case scenario for the chlorine dioxide uses.  For
terrestrial animals, the results of studies show that toxicity of
chlorine dioxide/sodium chlorite to birds ranges from highly to slightly
toxic to birds on an acute oral basis and from slightly toxic to
practically non-toxic on a subacute dietary basis.  

For freshwater aquatic animals, the results of studies examining the
toxicity of chlorine dioxide/sodium chlorite to freshwater fish indicate
these chemicals range from slightly toxic to practically non-toxic on an
acute basis.  For aquatic invertebrates, the studies indicate that
chlorine dioxide and sodium chlorite range from very highly toxic for
technical grade sodium chlorite to practically non-toxic for the
formulated product on an acute basis.  Results of toxicity studies
indicate that chlorine dioxide/sodium chlorite are slightly toxic to
estuarine/marine fish on an acute basis and range from highly toxic to
slightly toxic to estuarine/marine invertebrates on an acute basis.  

For terrestrial plants, results of toxicity studies indicate that
chlorine dioxide/sodium chlorite are moderately toxic to terrestrial
plants.  For aquatic plants, toxicity study results indicate chlorine
dioxide/sodium chlorite are moderately toxic to aquatic plants.  

 For aquatic organisms, acute risk is anticipated from the use of
chlorine dioxide/sodium chlorite in once-through cooling towers based on
the modeling conducted.  At the highest doses, there is risk to
freshwater and marine/estuarine fish and invertebrates and aquatic
plants, and at the lowest doses there is risk only to freshwater
invertebrates.  Chronic risk to aquatic organisms cannot be assessed at
this time due to the lack of chronic toxicity endpoints for fish and
aquatic invertebrates.  When the required aquatic chronic toxicity
testing described above is submitted, chronic risk to these organisms
will be assessed.

The once-through cooling tower use of chlorine dioxide/sodium chlorite
has been selected for risk assessment because out of all the uses of
these chemicals, it is the one expected to have the most potential for
environmental exposure.  The environmental risk assessment was conducted
using sodium chlorite endpoints because under environmental conditions,
chlorine dioxide converts mostly into chlorite ions.  

Listed Species Consideration

			a.	The Endangered Species Act   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision:D. Regulatory
Rationale: 4. Threatened and Endnagered Species Considerations: a. The
Endangered Species Program"  

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2),
requires all federal agencies to consult with the National Marine
Fisheries Service (NMFS) for marine and anadromous listed species, or
the United States Fish and Wildlife Services (FWS) for listed wildlife
and freshwater organisms, if they are proposing an “action” that may
affect listed species or their designated habitat.  Each federal agency
is required under the Act to insure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence
of a listed species or result in the destruction or adverse modification
of designated critical habitat.  To jeopardize the continued existence
of a listed species means “to engage in an action that reasonably
would be expected, directly or indirectly, to reduce appreciably the
likelihood of both the survival and recovery of a listed species in the
wild by reducing the reproduction, numbers, or distribution of the
species.” 50 C.F.R. § 402.02.

To facilitate compliance with the requirements of the Endangered Species
Act subsection (a)(2) the Environmental Protection Agency, Office of
Pesticide Programs has established procedures to evaluate whether a
proposed registration action may directly or indirectly reduce
appreciably the likelihood of both the survival and recovery of a listed
species in the wild by reducing the reproduction, numbers, or
distribution of any listed species (U.S. EPA, 2004).  After the
Agency’s screening-level risk assessment is performed, if any of the
Agency’s Listed Species LOC Criteria are exceeded for either direct or
indirect effects, a determination is made to identify if any listed or
candidate species may co-occur in the area of the proposed pesticide
use.  If determined that listed or candidate species may be present in
the proposed use areas, further biological assessment is undertaken. 
The extent to which listed species may be at risk then determines the
need for the development of a more comprehensive consultation package as
required by the Endangered Species Act.

Acute risk to listed birds and mammals is not anticipated from the use
of chlorine dioxide and sodium chlorite products due to low exposure and
low toxicity.  Further evaluation is needed before it can be determined
if there are risks to listed aquatic organisms from the once through
cooling tower use of chlorine dioxide/sodium chlorite.  Chronic risks to
listed aquatic organisms cannot be assessed at this time; this risk will
be assessed when required chronic toxicity data are submitted to and
evaluated by the Agency.  These conclusions are based solely on EPA’s
screening-level assessment and do not constitute “may effect”
findings under the Endangered Species Act for any listed species.  

IV.  	Risk Management, Reregistration, and Tolerance Reassessment
Decision  XE "IV. Risk Management, Reregistration, and Tolerance
Reassessment Decision"  

								

	A.  	Determination of Reregistration Eligibility   XE "IV. Risk
Management, Reregistration, and Tolerance Reassessment Decision: A.
Determination of Reregistration Eligibility" \i  

	Section 4(g)(2)(A) of FIFRA calls for the Agency to determine, after
submission of relevant data concerning an active ingredient, whether or
not products containing the active ingredient are eligible for
reregistration.  The Agency has previously identified and required the
submission of the generic (i.e., active ingredient-specific) data
required to support reregistration of products containing chlorine
dioxide and sodium chlorite as an active ingredient.  The Agency has
completed its review of these generic data, and has determined that the
data are sufficient to support reregistration of all supported products
containing chlorine dioxide and sodium chlorite.

	The Agency has completed its assessment of the dietary, occupational,
drinking water, and ecological risks associated with the use of
pesticide products containing the active ingredient chlorine dioxide and
sodium chlorite.  Based on a review of these data and on public comments
on the Agency’s assessments for the active ingredient chlorine dioxide
and sodium chlorite, the Agency has sufficient information on the human
health and ecological effects of chlorine dioxide and sodium chlorite to
make decisions as part of the tolerance reassessment process under FFDCA
and reregistration process under FIFRA, as amended by FQPA.  The Agency
has determined that all chlorine dioxide and sodium chlorite
pesticide-containing products are eligible for reregistration provided
that: (i) current data gaps and confirmatory data needs are addressed;
(ii) the risk mitigation measures outlined in this document are adopted;
and (iii) label amendments are made to reflect these measures.  Label
changes are described in Section V.  Appendix A summarizes the uses of
chlorine dioxide and sodium chlorite that are eligible for
reregistration.  Appendix B identifies the generic data requirements
that the Agency reviewed as part of its determination of reregistration
eligibility of chlorine dioxide and sodium chlorite, and lists the
submitted studies that the Agency found acceptable.  Data gaps are
identified as generic data requirements that have not been satisfied
with acceptable data.

	Based on its evaluation of chlorine dioxide and sodium chlorite, the
Agency has determined that chlorine dioxide and sodium chlorite
products, unless labeled and used as specified in this document, would
present risks inconsistent with FIFRA.  Accordingly, should a registrant
fail to implement any of the risk mitigation measures identified in this
document, the Agency may take regulatory action to address the risk
concerns from the use of chlorine dioxide and sodium chlorite.  If all
changes outlined in this document are incorporated into the product
labels, then all current risks for chlorine dioxide and sodium chlorite
will be substantially mitigated for the purposes of this determination. 
Once an Endangered Species assessment is completed, further changes to
these registrations may be necessary as explained in Section III of this
document.

B.  	Public Comments and Responses   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision: B. Public Comments
and Responses" \i  

	Through the Agency’s public participation process, EPA worked with
stakeholders and the public to reach the regulatory decisions for
chlorine dioxide and sodium chlorite.  During the public comment period
on the risk assessments, which closed on June 26 ,2006, the Agency
received comments from the registrants, Chlorine Dioxide Panel and other
interested parties.  These comments in their entirety, as well as the
risk assessments for chlorine dioxide, are available in the public
docket (EPA-HQ-OPP-2006-0328) at   HYPERLINK
"http://www.regulations.gov/"  http://www.regulations.gov/ .   The
Agency’s responses to these comments are incorporated into the risk
assessment and revised chapters, which are also available in the public
docket.  

	C.  	Regulatory Position   XE "IV. Risk Management, Reregistration, and
Tolerance Reassessment Decision:C. Regulatory Posistion" \i  

				

		1.	Food Quality Protection Act Findings   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision: C. Regulatory
Position: 1. Food Quality Protection Act Findings"  

			

			a.  	“Risk Cup” Determination   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision: C. Regulatory
Position: 1. Food Quality Protection Act Findings: a. "Risk Cup"
Determination"  

As part of the FQPA tolerance reassessment process, EPA assessed the
risks associated with this pesticide.  The Agency has determined that,
if the mitigation described in this document is adopted and labels are
amended, human health risks as a result of exposures to sodium chlorite
are within acceptable levels.  In other words, EPA has concluded that
the exemptions from tolerances for sodium chlorite meet FQPA safety
standards.  In reaching this determination, EPA has considered the
available information on the special sensitivity of infants and
children, as well as exposures to sodium chlorite from all possible
sources.  		

b.	Determination of Safety to U.S. Population

  SEQ CHAPTER \h \r 1 	As part of the FQPA tolerance reassessment
process, EPA assessed the risks associated with chlorine dioxide and
sodium chlorite. The Agency has determined that, taking into
consideration that a safety finding was made for sodium chlorate in the
Inorganic Chlorates RED, the established tolerance exemptions for
chlorine dioxide and sodium chlorite, with amendments and changes as
specified in this document, meet the safety standards under the FQPA
amendments to section 408(b)(2)(D) of the FFDCA, and that there is a
reasonable certainty no harm will result to the general population or
any subgroup from the use of chlorine dioxide and sodium chlorite.  In
reaching this conclusion, the Agency has considered all available
information on the toxicity, use practices and exposure scenarios, and
the environmental behavior of chlorine dioxide and sodium chlorite.  As
discussed in Section III, the acute, and chronic dietary (food and
drinking water) risks from chlorine dioxide and sodium chlorite are
below the Agency’s level of concern, provided that mitigation measures
outlined in this document and the and the Inorganic Chlorates RED are
adopted and labels are amended.  

		c.  	Determination of Safety to Infants and Children   XE "IV. Risk
Management, Reregistration, and Tolerance Reassessment Decision:C.
Regulatory Position: 1. Food Quality Protection Act Findings: c.
Determination of Safety to Infants and Children "  

	EPA has determined that the tolerance exemptions for chlorine dioxide
and sodium chlorite, with amendments and changes as specified in this
document, meet the safety standards under the FQPA amendments to section
408(b)(2)(C) of the FFDCA, that there is a reasonable certainty of no
harm for infants and children.  The safety determination for infants and
children considers factors of the toxicity, use practices, and
environmental behavior noted above for the general population, but also
takes into account the possibility of increased dietary exposure due to
the specific consumption patterns of infants and children, as well as
the possibility of increased susceptibility to the toxic effects of
chlorine dioxide and sodium chlorite residues in this population
subgroup.  

In determining whether or not infants and children are particularly
susceptible to toxic effects from exposure to residues of chlorine
dioxide/sodium chlorite, the Agency considered the completeness of the
hazard database for developmental and reproductive effects, the nature
of the effects observed, and other information.  On the basis of this
information, the FQPA safety factor has been reduced to 1X for chlorine
dioxide/sodium chlorite.  The rational for the decisions are based on:
(1) the existence of a complete developmental and reproductive toxicity
database; (2) the endpoint selected for assessment of risk from dietary
and non-dietary exposure to chlorine dioxide is protective of
potentially susceptible populations including children and (3) the risk
assessment does not underestimate the potential exposure for infants and
children.  

			d.  	Endocrine Disruptor Effects   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision:C. Regulatory
Position: 1. Food Quality Protection Act Findings: d. Endocrine
Disruptor Effects"  

	

EPA is required under the Federal Food Drug and Cosmetic Act (FFDCA), as
amended by FQPA, to develop a screening program to determine whether
certain substances (including all pesticide active and other
ingredients) “may have an effect in humans that is similar to an
effect produced by a naturally occurring estrogen, or other such
endocrine effects as the Administrator may designate.”  Following
recommendations of its Endocrine Disruptor and Testing Advisory
Committee (EDSTAC), EPA determined that there was a scientific basis for
including, as part of the program, the androgen and thyroid hormone
systems, in addition to the estrogen hormone system.  EPA also adopted
EDSTAC’s recommendation that the Program include evaluations of
potential effects in wildlife.  For pesticide chemicals, EPA will use
FIFRA and, to the extent that effects in wildlife may help determine
whether a substance may have an effect in humans, FFDCA authority to
require the wildlife evaluations.  As the science develops and
resources allow, screening of additional hormone systems may be added to
the Endocrine Disruptor Screening Program (EDSP).

			e.  	Cumulative Risks   XE "IV. Risk Management, Reregistration, and
Tolerance Reassessment Decision:C. Regulatory Position: 1. Food Quality
Protection Act Findings: e. Cumulative Risks"  

	Risks summarized in this document are those that result only from the
use of chlorine dioxide and sodium chlorite.  The Food Quality
Protection Act (FQPA) requires that the Agency consider “available
information” concerning the cumulative effects of a particular
pesticide’s residues and “other substances that have a common
mechanism of toxicity.”  The reason for consideration of other
substances is due to the possibility that low-level exposures to
multiple chemical substances that cause a common toxic effect by a
common toxic mechanism could lead to the same adverse health effect as
would a higher level of exposure to any of the substances individually. 
Unlike other pesticides for which EPA has followed a cumulative risk
approach based on a common mechanism of toxicity, EPA has not made a
common mechanism of toxicity finding for chlorine dioxide and sodium
chlorite.  For information regarding EPA’s efforts to determine which
chemicals have a common mechanism of toxicity and to evaluate the
cumulative effects of such chemicals, see the policy statements released
by EPA’s Office of Pesticide Programs concerning common mechanism
determinations and procedures for cumulating effects from substances
found to have a common mechanism on EPA’s website at     HYPERLINK
"http://www.epa.gov/pesticides/cumulative/" 
http://www.epa.gov/pesticides/cumulative/ .  

2.	Tolerance Reassessment Summary

Table 12 summarizes the reassessment of the chlorine dioxide tolerance
exemptions 

for sodium chlorite.  

	In order to support the use of chlorine dioxide/sodium chlorite as a
fruit and vegetable wash for Raw Agricultural Commodities that will not
be processed, a petition to establish a tolerance exemption must be
submitted.

Tolerances Currently Listed Under 40 CFR §180.940(b)(c) and 				
Tolerance Reassessment

  XE "IV. Risk Management, Reregistration, and Tolerance Reassessment
Decision:C. Regulatory Position: 2. Tolerance Reassessment: a.
Tolerances Currently listed and Tolerance Reassessment"  

Table 12.  Tolerance Information Listed Under 40 CFR 180.1070

Expression	Commodity	Current Tolerance	Tolerance Reassessment	Use

Sodium chlorite 	 Brassica (cole) leafy vegetables 	Exempt

	Exempt 1	seed soak treatment in the growing of the raw agricultural
commodities crop group Brassica (cole) leafy vegetables and radishes

Sodium chlorite	Radishes	Exempt

	Exempt 1	seed soak treatment in the growing of the raw agricultural
commodities crop group Brassica (cole) leafy vegetables and radishes

Tolerance Exemption Expression	CAS No.	40 CFR 

	Use Pattern	Limits

Oxychloro species(including chlorine dioxide) generated by acidification
of an aqueous solution of sodium chlorite	N/A	180.940 (b)2(c)3
Food-contact surface sanitizing solution 	When ready for use, the
end-use concentration is not to exceed 200 ppm chlorine dioxide



Tolerance Exemption Expression	CAS No.	40 CFR 

	Use Pattern	Limits

Oxychloro species (predominately chlorite, chlorate and chlorine dioxide
in an equilibrium mixture) generate either  (i) by directly metering a
concentrated chlorine dioxide solution prepared just prior to use, into
potable water, or (ii) by acidification of an aqueous alkaline solution
of oxychloro species (predominately chlorite and chlorate) followed by
dilution with potable water	N/A	180.940 (c)3	Food-contact surface
sanitizing solution 	When ready for use, the end-use concentration is
not to exceed 200 ppm chlorine dioxide

Residues listed under 40 CFR §180.1070 are exempted from the
requirement of a tolerance  when used as a  seed soak treatment in the
growing of the raw agricultural commodities group listed

Under 40 CFR §180.940(b), chemical substances when use as ingredients
in an antimicrobial pesticide formulation may be applied to dairy
processing equipment, and food-processing equipment and utensils.

Under 40 CFR §180.940 (c), chemical substances when used as ingredients
in an antimicrobial pesticide formulation may be applied to
food-processing equipment and utensils.

b.	Codex/International Harmonization

There are no Codex maximum residue limits (MRLs) for sodium chlorite.

D.	Regulatory Rationale   XE "IV. Risk Management, Reregistration, and
Tolerance Reassessment Decision:D. Regulatory Rationale"  

	The Agency has determined that chlorine dioxide and sodium chlorite are
eligible for reregistration provided that additional required data
confirm this decision and that the risk mitigation measures outlined in
this document are adopted, and label amendments are made to reflect
these measures.  

	The following is a summary of the rationale for managing risks
associated with the use of chlorine dioxide and sodium chlorite.  Where
labeling revisions are warranted, specific language is set forth in the
Table 13 of Section V of this document.  

		1.	Human Health Risk Management   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision: D. Regulatory
Rationale: 1. Human Health Risk Management"  

			a.	Dietary (Food) Risk Mitigation   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision:D. Regulatory
Rationale:1. Human Health Risk Management: a. Dietary (Food) Risk
Mitigation"  

Acute Dietary (Food) Risk										

	

No acute dietary endpoint was selected because effects attributable to a
single dose were not seen in the available data; therefore, an acute
dietary risk assessment was not conducted.  

Chronic Dietary (Food) Risk

Although there is not a concern for chronic dietary risk estimates for
all populations.  Dietary exposure from food did have an impact of the
aggregate assessment for children which is of concern (MOE = 44).  The
individual exposure received from the post-harvest application of sodium
chlorite to fruits and vegetables is an extremely high-end estimate. 
This assessment was conducted with the most conservative assumptions and
resulted in an estimate of 42% of the cPAD for children.  For example,
this assessment assumed that all fruits and vegetables in the U.S. had a
chlorine dioxide solution applied and that these commodities were not
washed, cooked or processed prior to consumption.  Additionally, the
Chlorine Dioxide Panel has agreed to limit the residual concentration of
chlorine dioxide to 3 ppm for post-harvest application to fruits and
vegetables that are not raw agricultural commodities.  Therefore, fruits
and vegetables treated with chlorine dioxide must be followed by
blanching, cooking or canning.  Although the Agency cannot quantify the
reduction of chlorine dioxide dietary exposure at this time, it is
believed that this measure would significantly reduce the percent of
chlorine dioxide cPAD resulting from this use.  No additional dietary
risk mitigation measures are required to address exposure to chlorine
dioxide and sodium chlorite residues in food.  Further, these
conservatisms and label changes also mitigate the aggregate risks to
children so that they are no longer of concern.

		b.	Safe Drinking Water Act

When determining whether a pesticide tolerance is safe, EPA must
consider the factors listed in section 408(d) of the FFDCA.  One of
these factors is the consideration of other non-occupational pesticidal
exposures.  For chlorine dioxide and sodium chlorite, exposures occur
through drinking water from treatment plant disinfection.  These
exposures need to be considered when reassessing the tolerances
associated with the registered uses of these pesticides.   

Chlorine dioxide and sodium chlorite are used to disinfect water in
treatment plants in order to meet the Safe Drinking Water Act’s (SDWA)
requirements to protect drinking water.  In addition to the statute, 40
C.F.R. section 141.72 states, “A public water system that uses a
surface water source and does not provide filtration treatment must
provide the disinfection treatment  . . . .” The required residual of
the disinfectant chlorine dioxide is specified in 40 C.F.R. 141.74.    

The SDWA was originally passed by Congress in 1974 to protect public
health by regulating the nation's public drinking water supply. The law
was amended in 1986 and 1996 and requires many actions to protect
drinking water and its sources: rivers, lakes, reservoirs, springs, and
ground water wells. (SDWA does not regulate water systems, which serve
fewer than 25 individuals.) SDWA authorizes the EPA to set national
health-based standards for drinking water to protect against both
naturally-occurring and man-made contaminants that may be found in
drinking water. EPA, states, and water systems then work together to
make sure that these standards are met.

Drinking water that is not properly treated or disinfected, or which
travels through an improperly maintained distribution system, may pose a
health risk.  SDWA applies to every public water system in the United
States. The responsibility for making sure these public water systems
provide safe drinking water is shared among EPA, states, tribes, water
systems, and the public. 

EPA sets national standards for drinking water based on sound science to
protect against health risks, considering available technology and
costs. These National Primary Drinking Water Regulations set enforceable
maximum contaminant levels (MCL) for particular contaminants in drinking
water or required ways to treat water to remove contaminants. Each
standard also includes requirements for water systems to test for
contaminants in the water to make sure standards are achieved. As listed
in 40 CFR 141.53 EPA has set the MCL at 0.1 mg/L for sodium chlorite. 

To ensure that drinking water is safe, SDWA sets up multiple barriers
against pollution.  One such barrier is treatment.  Public water systems
are responsible for ensuring that contaminants in tap water do not
exceed the standards.  Water systems treat the water, and must test
their water frequently for specified contaminants and report the results
to states.  If a water system is not meeting these standards, it is the
water supplier's responsibility to notify its customers. 

EPA sets primary drinking water standards through a three-step process:

First, EPA identifies contaminants that may adversely affect public
health and occur in drinking water with a frequency and at levels that
pose a threat to public health.  EPA identifies these contaminants for
further study, and determines contaminants to potentially regulate. 

Second, EPA determines a maximum contaminant level goal for contaminants
it decides to regulate.  This goal is the level of a contaminant in
drinking water below which there is no known or expected risk to health.
 These goals allow for a margin of safety. 

Third, EPA specifies a maximum contaminant level, the maximum
permissible level of a contaminant in drinking water which is delivered
to any user of a public water system.  These levels are enforceable
standards, and are set as close to the goals as feasible.  SDWA defines
feasible as the level that may be achieved with the use of the best
technology, treatment techniques, and other means which EPA finds (after
examination for efficiency under field conditions) are available, taking
cost into consideration.  When it is not economically or technically
feasible to set a maximum level, or when there is no reliable or
economic method to detect contaminants in the water, EPA instead sets a
required Treatment Technique which specifies a way to treat the water to
remove contaminants.

EPA sets national standards for tap water which help ensure consistent
quality in our nation's water supply.  EPA prioritizes contaminants for
potential regulation based on risk and how often they occur in water
supplies.  (To aid in this effort, certain water systems monitor for the
presence of contaminants for which no national standards currently exist
and collect information on their occurrence). EPA sets a health goal
based on risk (including risks to the most sensitive populations, e.g.,
infants, children, pregnant women, the elderly, and the
immuno-compromised).  EPA then sets a legal limit for the contaminant in
drinking water or a required treatment technique.  This limit or
treatment technique is set to be as close to the health goal as
feasible.  

EPA also performs a cost-benefit analysis and obtains input from
interested parties when setting standards. 

EPA promulgated regulations to control microbial pathogens and
disinfectants/disinfection byproducts in drinking water in a multi-stage
process that dates back to a 1992-93 negotiated rulemaking, which was
affirmed by Congress in the 1996 Amendments to the SDWA.  The
regulations address complex risk trade-offs between the two different
types of contaminants and were promulgated with significant stakeholder
input.  (65 FR 83016)

Even though, the FFDCA standard in section 408 is a risk-based standard
and the SDWA is a cost-benefit standard, the Agency believes we must
consider the harm to human health broadly.  In doing so, the EPA does
not believe it to be prudent to cancel the drinking water disinfectant
use of chlorine dioxide and sodium chlorite as that action could
potentially result in harming the public at large.  The Agency believes
the mitigation measures required in this document for the food uses that
require pesticide tolerances will reduce exposures from those uses such
that the exposures will result in a minimal addition to the exposure
that occurs from drinking water.  The Agency is reasonably certain that
this minimal addition does not cause harm to human health, and is
therefore safe under section 408(b) of the FFDCA.

c.	Drinking Water Risk Mitigation

	Drinking water risks of concern were identified for infants.  Drinking
water exposure also played a role in the aggregate risks of concern for
children.

The chlorite ion (ClO2-) is a major degradation product resulting from
the reaction of chlorine dioxide with inorganic and organic constituents
in the water.  When free chlorine is used after the application of
chlorine dioxide in the treatment process, chlorite is oxidized to
chlorate.  Chlorite oxidizes to chlorate over a period of time in water
and soil.  This conversion will continue over time as the water travels
through the distribution system.  Treatment of public water supplies is
necessary to kill pathogens that may exist in the drinking water, such
as cholera, typhoid, and dysentery.  Outbreaks of these diseases
decreased significantly when disinfection of the water systems was
introduced in the early 1900s.  While there are many important public
functions of water treatment, the Agency is taking steps to limit the
exposure of chlorite ion as a disinfection byproduct to the public. 
Approximately six percent of U.S. water treatment facilities use
chlorine dioxide for water disinfection.

In addition, the Chlorine Dioxide Panel recently submitted a study that
evaluated whether the components of the baby formula react with the
chlorite in drinking water to form chloride, which is not of concern in
drinking water because it is easily absorbed and metabolized by the
body.  A preliminary review of the data suggests that the components of
the baby formula, such as ascorbic acid, react with chlorite in the
drinking water.  Specifically, within five minutes of adding the formula
to the water, approximately one third of the chlorite combines with the
ingredients in the infant formula to form chloride.

The Agency is not currently able to quantify the reduction of exposure
to chlorite that occurs due to binding of chlorite with ingredients
present in the baby formula.  However, based on its initial evaluation
of the existing data, the Agency believes that for all infants the %
cPAD will likely be close to the target of 100, and not of concern.  The
Agency will require additional data on the breakdown of chlorite in baby
formula as confirmatory data.  

As mentioned above, the aggregate risks to children 1-6 are mitigated by
the consideration discussed concerning dietary exposures from food.

d.	Residential Risk Mitigation   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision:D. Regulatory
Rationale: 1. Human Health Risk Management: c. Residential Risk
Mitigation"  

				

Residential Handler

Residential risks for handlers were calculated for short- and
intermediate-term dermal and inhalation exposures.  Risks of concern
were identified for homeowners who place tablets in swimming pools/spas
with their bare hands (MOE=46).  This risk will be mitigated if the
homeowner wears gloves while placing the tablet in the swimming pool/spa
(MOE=500).  Although the Agency does not normally require the use of
personal protective equipment such as gloves, on pesticidal products
that are used in and around the home, the use of gloves in this case is
thought to be prudent since the Agency expects that, given the nature of
pool products of this kind, residents are likely to wear gloves based on
a perception of the danger of the chemicals along with the label
warnings and precautions.  This is not necessarily expected to be true
of most other residential products where Personal Protective Equipment
(PPE)  would not be considered an effective mitigation measure nor
should this be viewed as a precedent for requiring use of PPE for
residential use products.  All other exposure and risk estimates for
residential handler scenarios are below the Agency’s level of concern.
 

	

			ii.	Residential Post-Application

The Agency has conducted dermal, incidental oral and inhalation exposure
assessments for residential post-application scenarios.

The residential use of chlorine dioxide/sodium chlorite continuous
release deodorizers are of concern.  To mitigate this risk, the
following use sites for the continuous release deodorizer are ineligible
for reregistration and must be deleted:  shoes, closets, laundry
hampers, bags, drawers, basements, boat cabins, trash bags, and
additional deodorizing uses.  The remaining use sites will be in an
outdoor or commercial setting where people are not likely to have
prolonged exposure, e.g., dumpsters. Therefore, the risks from this use
pattern would be considered to be no longer of concern.  The registrant
has agreed to voluntarily cancel these use patterns.

Based on the risk assessment, a post-application inhalation concern was
identified for adults and children exposed to carpets treated with
chlorine dioxide/sodium chlorite.  In order to mitigate this risk, the
registrants must prohibit residential use; however, a commercial
application to carpet will remain registered with a one hour Restricted
Entry Interval (REI).

e.	Aggregate Risk Mitigation

Intermediate- and Short-Term

The short- and intermediate- risks to infants are primarily driven by
exposure to residues in drinking water.  These exposures and risks are
mitigated as described in the drinking water section above.   The short-
and intermediate- risks to children are largely driven by the dietary
exposure through food.  The characterization and mitigation described
above for risks from exposure to residues in food address the aggregate
risk as well.  Based on these characterization and mitigation measures,
the Agency believes that aggregate risks are not of concern. 

Chronic

The chronic risks to infants are primarily driven by exposure to
residues in drinking water.  These exposures and risks are mitigated as
described in the drinking water section above.   The chronic risks to
children are largely driven by the dietary exposure through food.  The
characterization and mitigation described above for risks from exposure
to residues in food address the aggregate risk as well.  Based on these
characterization and mitigation measures, the Agency believes that
aggregate risks are not of concern.

f.	  XE "IV. Risk Management, Reregistration, and Tolerance Reassessment
Decision:D. Regulatory Rationale: 1. Human Health Risk Management: b.
Drinking Water Risk Mitigation"  Occupational Risk Mitigation   XE "IV.
Risk Management, Reregistration, and Tolerance Reassessment Decision:D.
Regulatory Rationale: 1. Human Health Risk Management: d. Occupational
Risk Mitigation"  

i.	Occupational Handler   XE "IV. Risk Management, Reregistration, and
Tolerance Reassessment Decision:D. Regulatory Rationale: 1. Human Health
Risk Management: d. Occupational Risk Mitigation: i. Handler Exposure"  

Dermal Risks from Applications in Agricultural and Medical Premises 

	The Agency has conducted dermal and inhalation exposure assessments for
handlers applying chlorine dioxide in an occupational setting.  Based on
this assessment, dermal risks of concern were identified for handlers
applying chlorine dioxide:  to hard surfaces using a low pressure hand
wand (MOE=31); to hard surfaces using a mop (MOE=70); to animal
transport vehicles/tractor trailer using a foam application (MOE=8 w/
gloves); and in food handling, commercial/institutional, and medical
premises and equipment using a mop (MOE=66 for commercial and MOE=3 for
medical).  

	These scenarios were evaluated using highly conservative assumptions
including the use of a 100% dermal absorption factor that assumes that
all chlorine dioxide/sodium chlorite that contacts the skin will be
absorbed.  Further, high-end application and use parameters were used to
develop the risk estimates.  Therefore, the Agency does not expect that
actual exposures would be as high as those calculated in the risk
assessment.

	For these scenarios, the risks will be mitigated by requiring handlers
to wear gloves during application.  Although there is no data to assess
most scenarios with handlers wearing gloves, the Agency is confident
that this mitigation will protect occupational handlers.  Therefore,
these risks are not of concern to the Agency.    

	For the foam application, the Chlorine Dioxide Panel has submitted
information indicating that the Agency has overestimated the risks
associated with this use.  Specifically, the information indicates that
the number of vehicles treated in a day is eight, using two quarts of
solution per vehicle.  The Agency assessed an application rate of 4 to 6
gallons per minute and assumed that this product was applied for ten
minutes per day.  Subsequently, EPA determined that the assessed
application rate was too high.  Based on the revised application rate,
the Agency does not have a concern with this risk, provided that gloves
are worn during the treatment.  Additional details can be found in
“Chlorine Dioxide Occupational and Residential Exposure Assessment,”
dated August 2, 2006.  

Dermal Risks from Swimming Pool Applications	

Occupational risks for handlers were calculated for short- and
intermediate-term dermal exposures.  Risks of concern were identified
for handlers who place tablets in public swimming pools with their bare
hands (MOE=5).  This risk will be mitigated if the handlers wear gloves
while placing the tablet in the swimming pool (MOE=120), and no
additional mitigation is required.  

Inhalation Risks from Non-fogging Applications

There is the potential for the off-gassing of chlorine dioxide during
some non-fogging occupational applications that are not totally enclosed
(e.g., aqueous solution sprays, mopping, open pouring, etc).  To address
the potential for inhalation exposure, EPA has obtained worker air
concentration measurements from OSHA for 7 industry Standard Industrial
Classification (SIC) codes.  The monitored air concentrations for
workers are stored in OSHA’s data base known as the Integrated
Management Information System (IMIS).  The inhalation endpoint selected
by EPA for an 8-hour time-weighted average (TWA) is 0.003 ppm, just
below OSHA’s limit of detection of 0.004 ppm.  Of the 33 TWA
measurements available in IMIS, 21 of those measurements were below the
limit of detection.  In addition, of the 33 TWA measurements, only 3
were at or above the OSHA PEL of 0.1 ppm.  At this point in time,
monitoring to EPA’s level of concern (i.e., 0.003 ppm) is not
technically feasible.  However, 64 percent of the samples indicate that
the air concentrations of chlorine dioxide are near or below the level
of concern.  Therefore, for non fogging uses of chlorine dioxide such as
open pouring of aqueous solutions or bystanders in pulp and paper mills
no additional mitigation is deemed necessary at this time.

Inhalation Risks from Fogging Applications

Inhalation exposure to the release of chlorine dioxide gas during the
mixing/loading/application of products producing chlorine dioxide may
occur.  There is a greater potential for chlorine dioxide gas formation
from fogging then an aqueous-based application such as mopping.  The air
concentration in a fogged area should be below the occupational RfC of
0.003 ppm before the room is entered by persons not wearing respiratory
protection.  

However, one scenario based on labeled application rates allows chlorine
dioxide fogging and misting applications while workers are in the room
if the level of chlorine dioxide does not exceed the TLV-TWA of 0.1 ppm.
 Based on this scenario, the occupational RfC of 0.003 ppm could be
exceeded if handlers are present.  Therefore, people must vacate the
premises during fogging treatments and a one-hour restricted entry
interval (REI) is required to address this risk.  

Environmental Risk Management 

Environmental risk for the once-through cooling tower use of chlorine
dioxide/sodium chlorite has been assessed because it has the most
potential for environmental exposure.  The risk assessment was conducted
using sodium chlorite endpoints because under environmental these
conditions, chlorine dioxide converts mostly into chlorite ions.  

Acute risk is anticipated for aquatic organisms from the use of chlorine
dioxide/sodium chlorite in once-through cooling towers.  At the highest
doses on current labels (25 ppm), there is risk to freshwater and
marine/estuarine fish and invertebrates and aquatic plants, and at the
lowest doses there is risk only to freshwater invertebrates.  To
mitigate this risk, the maximum application rate for this use pattern
must be reduced from 25 ppm to 5 ppm for intermittent applications.

Chronic risk to aquatic organisms cannot be assessed at this time due to
the lack of chronic toxicity endpoints for fish and aquatic
invertebrates.  When the required aquatic chronic toxicity testing
described above is submitted, chronic risk to these organisms will be
assessed. All other exposure and risk estimates are below the Agency’s
level of concern.  

3.	Other Labeling Requirements   XE "IV. Risk Management,
Reregistration, and Tolerance Reassessment Decision:D. Regulatory
Rationale: 3. Other Labeling Requirements"  

	In order to be eligible for reregistration, various use and safety
information will be included in the labeling of all end-use products
containing chlorine dioxide and sodium chlorite.  For the specific
labeling statements and a list of outstanding data, refer to Section V
of this RED document.  

4.	Threatened and Endangered Species Considerations   XE "IV. Risk
Management, Reregistration, and Tolerance Reassessment Decision:D.
Regulatory Rationale: 4. Threatened and Endnagered Species
Considerations"  

			a.	The Endangered Species Program 

  XE "IV. Risk Management, Reregistration, and Tolerance Reassessment
Decision:D. Regulatory Rationale: 4. Threatened and Endnagered Species
Considerations: a. The Endangered Species Program"  

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2),
requires all federal agencies to consult with the National Marine
Fisheries Service (NMFS) for marine and anadromous listed species, or
the United States Fish and Wildlife Services (FWS) for listed wildlife
and freshwater organisms, if they are proposing an "action" that may
affect listed species or their designated habitat.  Each federal agency
is required under the Act to insure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence
of a listed species or result in the destruction or adverse modification
of designated critical habitat.  To jeopardize the continued existence
of a listed species means "to engage in an action that reasonably would
be expected, directly or indirectly, to reduce appreciably the
likelihood of both the survival and recovery of a listed species in the
wild by reducing the reproduction, numbers, or distribution of the
species." 50 C.F.R. § 402.02.

To facilitate compliance with the requirements of the Endangered Species
Act subsection (a)(2) the Environmental Protection Agency, Office of
Pesticide Programs has established procedures to evaluate whether a
proposed registration action may directly or indirectly reduce
appreciably the likelihood of both the survival and recovery of a listed
species in the wild by reducing the reproduction, numbers, or
distribution of any listed species (U.S. EPA 2004).  After the
Agency’s screening-level risk assessment is performed, if any of the
Agency’s Listed Species LOC Criteria are exceeded for either direct or
indirect effects, a determination is made to identify if any listed or
candidate species may co-occur in the area of the proposed pesticide
use.  If determined that listed or candidate species may be present in
the proposed use areas, further biological assessment is undertaken. 
The extent to which listed species may be at risk then determines the
need for the development of a more comprehensive consultation package as
required by the Endangered Species Act.

For certain use categories, the Agency assumes there will be minimal
environmental exposure, and only a minimal toxicity data set is required
(Overview of the Ecological Risk Assessment Process in the Office of
Pesticide Programs U.S. Environmental Protection Agency - Endangered and
Threatened Species Effects Determinations, 1/23/04, Appendix A, Section
IIB, pg.81).  Chemicals in these categories therefore do not undergo a
full screening-level risk assessment, and are considered to fall under a
no effect determination.  The screening level model used in this
assessment indicates that there may be acute risks to listed aquatic
organisms from the once through cooling tower use of chlorine
dioxide/sodium chlorite.  Further, potential indirect effects on any
species dependent upon a species that experiences effects from use of
chlorine dioxide/sodium chlorite cannot be precluded based on the
screening level ecological risk assessment.  These findings are based
solely on EPA’s screening level assessment and do not constitute
“may effect” findings under the Endangered Species Act.  Due to
these circumstances, the Agency defers making a determination for the
cooling tower use of chlorine dioxide and sodium chlorite until
additional data and modeling refinements are available.  At that time,
the environmental exposure assessment of the cooling tower of chlorine
dioxide will be revised, and the risks to Listed Species will be
reconsidered.

b.	General Risk Mitigation   XE "IV. Risk Management, Reregistration,
and Tolerance Reassessment Decision:D. Regulatory Rationale: 4.
Threatened and Endnagered Species Considerations: b. General Risk
Mitigation"  

	Chlorine dioxide and sodium chlorite end use products (EPs) may also
contain other registered pesticides.  Although the Agency is not
proposing any mitigation measures for products containing Chlorine
dioxide and sodium chlorite specific to federally listed threatened and
endangered species, the Agency needs to address potential risks from
other end-use products.  Therefore, the Agency requires that users adopt
all threatened and endangered species risk mitigation measures for all
active ingredients in the product.  If a product contains multiple
active ingredients with conflicting threatened and endangered species
risk mitigation measures, the more stringent measure(s) must be adopted.



V.	What Registrants Need to Do  XE "V. What Registrants Need To Do"  

	The Agency has determined that chlorine dioxide and sodium chlorite are
eligible for reregistration provided that:  (i) additional data that the
Agency intends to require confirm this decision; and (ii) the risk
mitigation measures outlined in this document are adopted, and (iii)
label amendments are made to reflect these measures.  To implement the
risk mitigation measures, the registrants must amend their product
labeling to incorporate the label statements set forth in the Label
Changes Summary Table in Section B below (Table 13).  The additional
data requirements that the Agency intends to obtain will include, among
other things, submission of the following:

	For chlorine dioxide and sodium chlorite technical grade active
ingredient products, the registrant needs to submit the following items:
 

Within 90 days from receipt of the generic data call in (DCI):

1.  Completed response forms to the generic DCI (i.e., DCI response form
and requirements status and registrant’s response form); and, 

	2.  Submit any time extension and/or waiver requests with a full
written justification.

Within the time limit specified in the generic DCI:

1.  Cite any existing generic data which address data requirements or
submit new generic data responding to the DCI.  

	

Please contact ShaRon Carlisle at (703) 308-6427 with questions
regarding generic reregistration.

By US mail:						By express or courier service:

Document Processing Desk (DCI/AD)		Document Processing Desk (DCI/AD)

ShaRon Carlisle					ShaRon Carlisle

US EPA (7510P)					Office of Pesticide Programs (7510P)

1200 Pennsylvania Ave., NW				One Potomac Yard (South Building),
Washington, DC 20460				2777 South Crystal Drive

							Arlington, VA 22202

For end use products containing the active ingredient chlorine dioxide
and sodium chlorite, the registrant needs to submit the following items
for each product.

Within 90 days from the receipt of the product-specific data call-in
(PDCI):

1.  Completed response forms to the PDCI (PDCI response form and
requirements status and registrant’s response form); and,

2.  Submit any time extension or waiver requests with a full written
justification.

Within eight months from the receipt of the PDCI:

1.  Two copies of the confidential statement of formula (CSF) (EPA Form
8570-4);

2.  A completed original application for reregistration (EPA Form
8570-1).  Indicate on the form that it is an “application for
reregistration”;

3.  Five copies of the draft label incorporating all label amendments
outlined in Table 15 of this document;

4.  A completed form certifying compliance with data compensation
requirements (EPA Form 8570-34); 

5.  If applicable, a completed form certifying compliance with cost
share offer requirements (EPA Form 8570-32); and, 

6.  The product-specific data responding to the PDCI.

	Please contact Emily Mitchell at (703) 308-8583 with questions
regarding product reregistration and/or the PDCI.  All materials
submitted in response to the PDCI should be addressed as follows:

By US mail:						By express or courier service:		

Document Processing Desk (PM-32)		            Document Processing Desk
(PM-32)	

Emily Mitchell					Emily Mitchell

US EPA (7510P)					Office of Pesticide Programs (7510P) 

1200 Pennsylvania Ave., NW				One Potomac Yard (South Building),
Washington, DC 20460				2777 South Crystal Drive

A.	Manufacturing Use Products   XE "V. What Registrants Need to Do:A.
Manufacturing Use Products"  

		1.	Additional Generic Data Requirements   XE "V. What Registrants Need
to Do:A. Manufacturing Use Products: 1. Additional Generic Data
Requirements"  

The generic database supporting the reregistration of chlorine dioxide
and sodium chlorite has been reviewed and determined to be substantially
complete.  However, the following additional data requirements have been
identified by the Agency as confirmatory data requirements.  A generic
data call-in will be issued at a later date.  Several Ecological studies
are being required to support the once-through cooling tower use of
chlorine dioxide/sodium chlorite.

The risk assessment noted deficiencies in the surrogate dermal and
inhalation exposure data available from the Chemical Manufacturers
Association (CMA) data base.  Therefore, the Agency is requiring
confirmatory data to support the uses assessed with the CMA exposure
data within this risk assessment.  The risk assessment also noted that
many of the use parameters (e.g., amount handled and duration of use)
were based on   SEQ CHAPTER \h \r 1 professional judgments.  Therefore,
descriptions of human activities associated with the uses assessed are
required as confirmatory.

Table 15.  Confirmatory Data Requirements for Reregistration

Guideline Study Name	New OPPTS Guideline No.	Old Guideline No.

Fish early life-stage testing-freshwater	850.1300	72-4

Invertebrate life-cycle testing - freshwater	850.1400	72-4b

Seedling emergence dose-response in rice	850.4225	123-1

Vegetative vigor dose-response in rice	850.4250	123-1

Aquatic vascular plant dose-response toxicity- Lemna sp.	850.4400	123-2

Acute algal dose-response toxicity - 4 species	850.5400	123-2

Indoor Inhalation Exposure and Applicator Exposure Monitoring Data
Reporting 	875.1400 and 875.1600	234 and 236

Indoor Dermal Exposure and Applicator Exposure Monitoring Data Reporting
875.1200 and 875.1600	233 and 236

Descriptions of Human Activity	875.2800	133-1

Carcinogenicity	870.4200	83-2

Fate of chlorite in baby formula	Special study	Special study

Use and Usage Information on the Percent of Fruits and Vegetables that
are treated with Chlorine Dioxide





2.  	Labeling for Technical and Manufacturing Use Products   XE "V. What
Registrants Need to Do:A. Manufacturing Use Products: 2. Labeling for
Technical and Manufacturing Use Products"  

	To ensure compliance with FIFRA, technical and manufacturing use
product (MP) labeling should be revised to comply with all current EPA
regulations, PR Notices and applicable policies.  The Technical and MP
labeling should bear the labeling contained in Table 16, Label Changes
Summary Table.

B.  	End-Use Products   XE "V. What Registrants Need to Do:B. End-Use
Products"  

		1.	Additional Product-Specific Data Requirements   XE "V. What
Registrants Need to Do:B. End-Use Products: 1. Additional
Product-Specific Data Requirements"  

	Section 4(g)(2)(B) of FIFRA calls for the Agency to obtain any needed
product-specific data regarding the pesticide after a determination of
eligibility has been made.  The Registrant must review previous data
submissions to ensure that they meet current EPA acceptance criteria and
if not, commit to conduct new studies.  If a registrant believes that
previously submitted data meet current testing standards, then the study
MRID numbers should be cited according to the instructions in the
Requirement Status and Registrants Response Form provided for each
product.

	A product-specific data call-in, outlining specific data requirements,
will follow this RED at a later date.

		2.	Labeling for End-Use Products   XE "V. What Registrants Need to
Do:B. End-Use Products: 2. Labeling for End-Use Products"  

	Labeling changes are necessary to implement measures outlined in
Section IV above.  Specific language to incorporate these changes is
specified in Table 16.

	Registrants may generally distribute and sell products bearing old
labels/labeling for 26 months from the date of the issuance of this
Reregistration Eligibility Decision document.  Persons other than the
registrant may generally distribute or sell such products for 52 months
from the approval of labels reflecting the mitigation described in this
RED.  However, existing stocks time frames will be established
case-by-case, depending on the number of products involved, the number
of label changes, and other factors.  Refer to “Existing Stocks of
Pesticide Products; Statement of Policy,” Federal Register, Volume 56,
No. 123, June 26, 1991.

a.	Label Changes Summary Table

In order to be eligible for reregistration, amend all product labels to
incorporate the risk mitigation measures outlined in Section IV.  The
following table describes how language on the labels should be amended.

Table 16.  Labeling Changes Summary Table	

Description	Amended Labeling Language	Placement on Label

Manufacturing Use Product

Supported Use Sites	“Only for formulation into antimicrobial products
for use in: agricultural/farm premises, structures, buildings, and
equipment; dairy farm milk handling facilities, equipment, storage
rooms, houses, and sheds; food processing plants, food handling, food
distribution equipment and premises; eating establishments premises and
equipment; commercial, institutional, and industrial premises and
equipment (floors, walls, storage areas); domestic dwellings, food
handling areas, indoor premises; and medical institutional critical care
and non-critical care premises, human water systems, swimming pools and
industrial processes and water systems.”

For Formulation into antimicrobial products for use in: animal transport
vehicles, carpets,  fountains/water displays/decorative ponds/, once-
through and recirculating industrial commercial cooling water systems,
pulp/paper mill water systems, and swimming pools, mushroom
facilities/premises and equipment, egg handling equipment and rooms, egg
washing treatment, chick room, poultry houses chiller water/carcass
spray, food processing plants/equipment, dairies/breweries and bottling
plants/equipment, fruit and vegetable rinse/process water and tank
lines, potable drinking water, water storage systems (aircrafts boats,
RVs, off-shore oil rigs), water filtration systems, ventilation systems.
	Directions for Use

PPE	

	Precautionary Statements

Ecological Effects Language Required by the RED and PR Notice 93-10 and
95-1	"This product is toxic to fish, aquatic invertebrates, oysters, and
shrimp.  Do not discharge effluent containing this product into lakes,
streams, ponds, estuaries, oceans, or other waters unless in accordance
with the requirements of a National Pollution Discharge Elimination
System (NPDES) permit and the permitting authority has been notified in
writing prior to discharge.  Do not discharge effluent containing this
product to sewer systems without previously notifying the local sewage
treatment plant authority.  For guidance contact your State Water Board
or Regional Office of the EPA."	Environmental Hazard Statements

End Use Products Intended for Occupational Use



Application Restrictions-For Occupational Handler -Dermal (Application
to hard surfaces)	“Handlers applying chlorine dioxide in an
occupational setting must wear gloves.”

low pressure hand wand (hard surfaces)

mop (hard surfaces)

foam application (animal transport vehicles/tractor trailer)

mop (food handling, commercial/institutional and medical
premises/equipment) 

	Precautionary Statements under:  Hazards to Humans and Domestic Animals
(Immediately Following Engineering Controls

Application Restrictions-For Occupational Handler -Dermal (Tablets into
public swimming pools)	“Occupational handler must wear gloves while
placing the tablet in the swimming pool”	Precautionary Statements
under:  Hazards to Humans and Domestic Animals (Immediately Following
Engineering Controls

Application Restrictions-For Occupational Handler –Inhalation 
(Fogging Use)	“People must vacate the premises during fogging
treatments; a one-hour restricted entry interval (REI) is required.”
Precautionary Statements under:  Hazards to Humans and Domestic Animals
(Immediately Following Engineering Controls

Application Restrictions-For Occupational – Inhalation (Carpet
Treatment)	"Not for residential use.  For nonresidential use, a one-hour
restricted entry interval is required."	Precautionary Statements under: 
Hazards to Humans and Domestic Animals (Immediately Following
Engineering Controls

Application Restrictions-For Occupational Post-Application  (Once
through use)	“Reduce the application rate from 25 ppm to 5 ppm for
intermittent applications.”



	End Use Products Intended for Residential Use



Application Restrictions-For Residential Handler -Dermal (Tablets into
pools/spas)	“Residential handler (homeowner) must wear gloves while
placing the tablet in the swimming pool/spa”	Precautionary Statements
under:  Hazards to Humans and Domestic Animals (Immediately Following
Engineering Controls

Application Restrictions-For Residential Post-Application – Inhalation
(Continuous release deodorizers) 	“Restrict to outdoor use only. Do
not use indoors (e.g., use in shoes, closets, laundry hampers, bags,
drawers, basements, boat cabins, trash bags, and any additional
deodorizing uses)”	Precautionary Statements under:  Hazards to Humans
and Domestic Animals (Immediately Following Engineering Controls

Application Restrictions-For Residential Post-Application – Inhalation
(Carpet Treatment)	“Residential use is prohibited.”	Precautionary
Statements under:  Hazards to Humans and Domestic Animals (Immediately
Following Engineering Controls

Dietary



Fruit and vegetable wash	“Fruits and vegetables treated with chlorine
dioxide must be blanched, cooked, or canned before consumption or
distribution in commerce”	Precautionary Statements under:  Hazards to
Humans and Domestic Animals (Immediately Following Engineering Controls





VI. APPENDICES  XE "VI. Appendices"  

Appendix A - Chlorine Dioxide, PC Code 020503

Use Site	Formulation/ EPA Reg No.	Method of Application	Application
Rate/ No. of applications	Use Limitations

Agricultural premises and equipment



Agricultural Storage Facilities

(Containers, Trailers, Rail Cars, Vessels)	Soluble Concentrate

9150-11	Foaming Wand	One quart to system that delivers 4-6 gallons per
minute of dilution water

10 minutes contact time	Preclean with water to remove debris and dirt.

Mushroom Facilities: (food Contact) Stainless Steel Tanks, Transfer
Lines, On-line Equipment, Picking Baskets	Soluble Concentrate

9150-2, 9150-3

9804-1, 58300-16, 58300-19

	Flush equipment with sanitizing solution	Use-solution calls for 100-200
ppm total available chlorine dioxide	Clean equipment and surfaces
thoroughly using a suitable detergent and rinse with water before
sanitizing.

Mushroom Facilities (non-food contact): disinfect walls ceilings and
floors	Soluble Concentrate

9150-2, 9150-3

9804-1, 58300-16, 58300-19	Spraying device	300-500 ppm total available
chlorine dioxide

1,000 ppm for control of mold and slime on walls	Remove all gross filth
from areas prior to disinfection. Never reuse activated solutions

Avoid contact with food or food contact surfaces.

Potato Facilities: (food Contact) Stainless Steel Tanks, Transfer Lines,
On-line Equipment, Handling equipment	Soluble Concentrate

9804-1	Fill, flush, immerse or spray	Use-solution calls for 100 ppm
total available chlorine dioxide	None stated

Potato Facilities: walls, ceilings floors, planting and harvesting
equipment and truck beds

Disinfection	Soluble Concentrate

9804-1	Spray	10 minute contact time	Always use an applicable NIOSH/MSHA
approved respirator appropriate for chlorine dioxide.

Potato Facilities: potato rinse tanks, flumes and lines	Soluble
Concentrate

9804-1	Chemical Feed pump or injector system	5 ppm	After Treatment
Potatoes must be rinsed with potable water.

Potato Storage: Potato rinse and humidification water	Soluble
Concentrate

9804-5

9150-12	Spray, mist and fogger	200 to 400 ppm 	No more than 20 gallons
of product concentrate per month to humidification water per 500 tons of
potatoes in storage.

Always use an applicable NIOSH/MSHA approved respirator appropriate for
chlorine dioxide.

Disinfection of Animal Confinement Facilities (Poultry Houses, Swine
Pens, Calf Barns and Kennels	Soluble Concentrate

9150-2, 9150-3

9804-1	Use Commercial Sprayer to saturate all surfaces	Working Solution
containing 300 to 500 ppm available Chlorine Dioxide	Remove all animals
and feed from premises. Remove all litter and manure from premises of
facilities. Empty all troughs , racks and other feeding equipment/
watering appliances. 

Thoroughly clean all surfaces with soap and detergent and rinse with
water.

	Soluble Concentrate

9150-11	None Stated	1000 ppm	Remove all animals, bedding, litter,
droppings and manure. Pre-clean

Animal Transport Vehicles	Soluble Concentrate

9150-11	Foaming Wand	One quart to system that delivers 4-6 gallons per
minute of dilution water

10 minutes contact time	Preclean with water to remove debris and dirt.

Control for odor and Slime forming  Bacteria in Animal Confinement
Facilities	Soluble Concentrate

9150-2, 9150-3	Commercial sprayer to saturate all surfaces	1,000 ppm
Remove all litter and manure from premises and thoroughly clean all
surfaces with soap or detergent and rinse with clean water

Shoe Bath	Soluble Concentrate	Immersion	1 to 2 ounces per galloon of
water	Change Shoe bath solution daily or when solution appears soiled.

Poultry House Disinfection:

Poultry Chiller Water/ Carcass spray	Soluble concentrate

9150-2, 9150-3	Dip Carcass	0.5 to 3 ppm for Chiller Water

70 ppm for Carcass Spray	None stated

Poultry Drinking Water	Soluble concentrate

9150-2, 9150-3	Add to water	5ppm for fouled water

0.5 to 1.0ppm for control	None stated

Egg Room/  Hatching Area

Incubator Room

Tray Washing Room and Loading Platform	Soluble Concentrate

9150-2, 9150-3	High pressure sprayer	20 ppm for pre wash w/ sprayer

390 ppm to preclean floors

1,000 ppm treatment w/ fogger	None Stated

	10589-3	Spray	5 oz. per gallon/ 1406 ppm (mixed with DDAC)	Remove gross
filth and heavy soil prior to application of the disinfecting solution

Chick Room, Chick Grading Box an Sexing room	Soluble concentrate

9150-2, 9150-3	Fogger, Mop	1,000 ppm w/ fogger

390 ppm to mop floors	None Stated

Hand Dip for Poultry Workers	Soluble concentrate

9150-2, 9150-3	Dip	50 ppm	None Stated

Horticulture uses 

Work Area and Benches

	Ready to use Solution 9150-11	Cloth, mop, sponge or sprayer	9 fl oz per
gallon/ 253 ppm	Do not Apply directly to Plant Material

Horticulture uses

Pots and Flats	Ready to use Solution 9150-11	Soak	18 fl oz per gallon/
506 ppm	Remove all loose soil and plant residue prior to application

Horticulture uses

Cutting Tools	Ready to use Solution 9150-11	Soak	9 fl oz per gallon/ 253
ppm	None Stated

Horticulture uses

Bulbs	Ready to use Solution 9150-11	Soak	9 to 18 fl oz per gallon/ 253
ppm to 506 ppm	None Stated

Horticulture uses

Greenhouse Glass, Walkways and under Bench Areas	Ready to use Solution
9150-11	Spray	4 to 9 fl oz per gallon/ 112 ppm to 253 ppm	None Stated

Evaporative Coolers	Ready to use Solution 9150-11	Add to water	4 to 9
fl. oz per gallon / 112 ppm to 253 ppm. Repeat as needed or every 14
days	None Stated

Rention Basins and Ponds	Ready to use Solution 9150-11	Add to Basin	4-9
fl oz. per 100 gallons/ 2 to 5 ppm	Do not use where fish are present

Decorative Pools, Fountains and Water Displays	Ready to use Solution
9150-11	Add to Pools	9-18 fl oz per 100 gallons/ 5 to 10 ppm	Do not use
where fish are present.

Food handling/ storage establishments premises and equipment



Food Processing Plants

(Poultry, Meat, Fish) 

Food Contact Surface Sanitizer	Soluble Concentrate

9150-2, 9150-3

9804-9

9804-1

	1 minute contact time	200ppm- 1,000 ppm total available chlorine
Dioxide

50 ppm

100 ppm	Preclean and rinse equipment. Do not reuse solution. Do not
rinse treated surface

Food Processing Plants

(Poultry, Meat, Fish) 

Non-Food contact disinfectant

	Soluble Concentrate

9804-9

9804-1

	Spray thoroughly wet for 10 minutes	500 ppm 	Never reuse activated
solutions

	Soluble Concentrate

10589-3	Spray	5 oz. per gallon/ 1406 ppm (mixed with DDAC)	Remove gross
filth and heavy soil prior to application of the disinfecting solution

Dairies, Breweries and Bottling Plants

Non-Food contact disinfectant

	Soluble Concentrate, Ready to use Solution

9804-9

9804-1	Spray thoroughly wet for 10 minutes	500 ppm	Never reuse activated
solutions

Dairies	Soluble Concentrate

10589-3	Spray	5 oz. per gallon/ 1406 ppm (mixed with DDAC)	Remove gross
filth and heavy soil prior to application of the disinfecting solution

Dairies, Breweries and Bottling Plants

Food Contact Surface Sanitizer	Soluble Concentrate, Ready to use
Solution

9150-2, 9150-3

9804-9

9804-1	1 minute contact time	200ppm- 1,000 ppm total available chlorine
Dioxide

50ppm

100ppm	Preclean and rinse equipment. Do not reuse solution. Do not rinse
treated surface

Ice Making Plants and Machinery	Soluble Concentrate, Ready to use
Solution

9804-9

9804-1

9804-5	Chemical Feed Pump or Injector System	20 ppm

	Lube Additive for Moving Conveyors and Chains	Soluble Concentrate,
Ready to use Solution

9804-9

9804-1	Inject into distribution system	10- 20 ppm	Preclean and sanitize
all conveyor surfaces and associated structures

Canning Retort and Pasteurizer Cooling Water	Soluble concentrate, Ready
to use Solution

9150-2, 9150-3

9804-9

	Controlled Chemical Feed Pump 	5ppm

	Stainless Steel Transfer Lines, Hydrocoolers and Pasteurizers	Soluble
concentrate, Ready to use Solution

9150-2, 9150-3

9804-9

9804-1	Mix and fill lines and Equipment overnight	20 ppm 	Preclean
equipment or line thoroughly 

Process Water for Vegetable Rinses, Tanks Lines	Soluble Concentrate

9150-2, 9150-3

9804-1	Chemical Feed Pump or injector system	5 ppm	Preclean all tanks,
flumes and lines with suitable detergent.

Fruit and Vegetable Rinse	Soluble concentrate

9150-2, 9150-3

9804-1	Immersion	1/3 fl. to 1 gallon of water per 25 gallons of water

5 ppm	Prewash whole fruits and vegetables with clean potable water.

Human Water Systems

Potable Drinking Water	Ready to Use solution

59055-1	Metering Pump

1 mg/ liter (1ppm) or less

1 gallon per 100,000 gallons of treated water	1 mg/ liter (1ppm) or less

1 gallon per 100,000 gallons of treated water	None Stated







	9150-2, 9150-3

9804-1

9804-5, 9150-9	None stated	5 ppm	None stated

Water Storage systems aboard Aircraft Boats, RV’s Off-shore Oil Rigs
Soluble concentrate

9150-2, 9150-3

9804-1	Add to tank and lines	50 to 500 ppm available chlorine dioxide
None stated

Municipal Well Waters	9150-2, 9150-3	None stated	1 ppm	None stated

Commercial water filtration systems	9804-1	Add to system	300 ppm	None
Stated

Commercial, institutional and industrial premises and equipment

Dental Offices

Dental Pumice Disinfectant	Soluble Concentrate

9150-3

9804-1	Apply to Dry Pumice	500 ppm	Discard 5 days after preparation

Hospitals and Nursing Homes

Institutions and Public Places

 General disinfectant	Soluble Concentrate

10589-3, 

9150-11

9804-1

	Spray	1000 ppm to 1406 ppm (mixed with DDAC)	Remove gross filth and
heavy soil prior to application of the disinfecting solution

Hospitals, Laboratories and Institutions

Hard Non Porous surfaces (Tile Floors, Walls and Ceilings and Stainless
Steel Cold Rooms)	Soluble Concentrate

9150-2, 9150-3

9804-1	Spray, Mop or sponge	Working Solution containing 300 to 500 ppm
available Chlorine Dioxide	Clean all surfaces with a suitable detergent
and rinse with water prior to disinfection.

Disinfection of Bench Tops, Biological Hoods, Incubators, Stainless
Steel Equipment and Instruments	Soluble Concentrate

9150-2, 9150-3

9804-1	Squirt onto surfaces with squeeze bottle	Working Solution
containing 300 to 500 ppm available Chlorine Dioxide	Clean all surfaces
with a suitable detergent and rinse with water prior to disinfection.

Water Bath Incubator	Soluble Concentrate

9150-2, 9150-3

9804-1	Pour solution into waterbath reservoir	Working Solution
containing 300 ppm available Chlorine Dioxide to disinfect

50 ppm for order and slime control	Clean reservoir with a suitable
detergent and rinse with water prior to disinfection

Sterilzation of Spent Biologicals in Steam Autoclaves	Soluble
Concentrate

9150-2, 9150-3	Spray or pour directly into autoclave buckets	Working
Solution containing 1,000 ppm available Chlorine Dioxide	None Stated

To Deodorize Animal Holding Rooms, Sick Rooms, Morgues and Work rooms
Soluble Concentrate

9150-2, 9150-3

9804-1	Spray solution on to walls ceilings and floors	Working Solution
containing 1,000 ppm available Chlorine Dioxide	Rooms to deodorize
should be ina clean condition prior to autoclaving.

Industrial Processing Plants	Soluble Concentrate

10589-3

	Spray	5 oz. per gallon/ 1406 ppm	Remove gross filth and heavy soil
prior to application of the disinfecting solution

Deodorizer- Hospitals, Restaurants, Hotel & Motel Rooms	Ready-to Use

9804-3	Spray	Spray area until covered with mist and let stand for 10
minutes	None stated

Swimming Pools

Swimming Pools	Ready to use solution

59055-1	Meetering Pump	1 to 5ppm  at a pH range from 7.2-7.6	None Stated

Residential and Public Access

Odors on Pets, Litter Boxes, Carpets and Concrete Floors	Soluble
concentrate

9150-2, 9150-3

9804-1	Soak, Mop or rinse	For litter boxes: 625 – 650ppm

For carpets: 500 ppm

Concrete floors: 1250 ppm

Animal Baths: 80-100 ppm	Avoid direct contact with animal’s eyes, nose
and ears

Ice Fishing in the Round Treatment	Soluble Concentrate

9150-2, 9150-3

9804-1	None stated	20 ppm 	None stated

Deodorizer- Restrooms/Bathrooms, Refuse Containers, diaper Pails,
Storage Lockers	Ready-to Use

9804-3	Spray	Spray area until covered with mist and let stand for 10
minutes	None stated

Industrial Processes and Water Systems

Water Cooling systems	Ready to Use,

Soluble concentrate

59055-1

9804-9

9804-1	Batch load or meter	100 ppm 

5.0 ppm	None Stated

Recirculating Cooling Water systems	Soluble concentrate,

Ready to use Solution

9150-2, 9150-3

9804-9	None stated	5-20 ppm	None stated

Water Based Cutting Oils	Soluble Concentrate 9150-2, 9150-3	Slug does
system	32 oz to 10 gallons per million gallons of cutting oil	None
stated

Paper Mills	Soluble Concentrate,

Ready to use Solution

9150-2, 9150-3

9804-9, 9804-1

	None stated	4.5 gallons product per 100 tons of paper

1.25 – 5.0 ppm (3.2 – 12.8 fluid ounces per 1,000 gallons of water
None stated

Oil Wells : Secondary Recovery Operations	Soluble Concentrate

9150-2, 9150-3	None Stated	5,000 ppm available chlorine dioxide	None
stated

Once Through Water Cooling Systems	Soluble Concentrate

9150-2, 9150-3	Slug and Continuous 	Slug Dose: 5-25 ppm

Continuous Dose: 0.25 to 2.0 ppm	None Stated



Ventilation systems	Soluble concentrate

9804-1	Spray or fog	500 ppm. 10 minute contact time	NIOSH/MSHA approved
respirator required 



Appendix A - Sodium Chlorite 020502

Use Site	Formulation/ EPA Reg No.	Method of Application	Application
Rate/ No. of applications	Use Limitations

Agricultural premises and equipment

Mushroom Facilities: (food Contact) Stainless Steel Tanks, Transfer
Lines, On-line Equipment, Picking Baskets	Soluble Concentrate/ Ready to
Use Solution

5382-46

58300-17

74602-2	Flush equipment with sanitizing solution	Use-solution calls for
100 ppm total available chlorine dioxide	Clean equipment and surfaces
thoroughly using a suitable detergent and rinse with water before
sanitizing.

Mushroom Facilities (non-food contact): disinfect walls ceilings and
floors	Soluble Concentrate/ Ready to use Solution

5382-46

58300-17

69151-5

74602-2	Spraying device	500 ppm total available chlorine dioxide

1,000 ppm for control of mold and slime on walls	Remove all gross filth
from areas prior to disinfection. Never reuse activated solutions

Avoid contact with food or food contact surfaces.

Potato Facilities: (food Contact) Stainless Steel Tanks, Transfer Lines,
On-line Equipment, Handling equipment	Soluble concentrate:

53345-20, 56485-4	Fill, flush, immerse or spray	Use-solution calls for
100 ppm total available chlorine dioxide	None stated

Potato Facilities: potato rinse tanks, flumes and lines	Soluble
concentrate:

53345-20, 56485-4, 9150-7	Chemical Feed pump or injector system

	5 ppm	After Treatment Potatoes must be rinsed with potable water.

Potato Storage: Potato rinse and humidification water	Soluble
concentrate:

53345-20, 56485-4, 21164-21	Spray, mist and fogger	200 to 400 ppm 	No
more than 20 gallons of product concentrate per month to humidification
water per 500 tons of potatoes in storage.

Always use an applicable NIOSH/MSHA approved respirator appropriate for
chlorine dioxide.



Disinfection of Animal Confinement Facilities (Poultry Houses, Swine
farrowing pens, Calf Barns and Kennels	Soluble Concentrate

70060-18, 45631-23, 74602-2, 70060-6, 74602-3, 70060-19, 69151-5, 8714-8
Mop, sponge or Use Commercial Sprayer to saturate all surfaces	Working
Solution containing 300 to 500 ppm available Chlorine Dioxide	Remove all
animals and feed from premises. Remove all litter and manure from
premises of facilities. Empty all troughs , racks and other feeding
equipment/ watering appliances. 

Thoroughly clean all surfaces with soap and detergent and rinse with
water.

Agricultural premises and equipment

Poultry House Disinfection:

Poultry Chiller Water/ Carcass spray	Soluble Concentrate

74602-2

9150-7

9150-8

74602-3

	Dip Carcass	0.11 to 0.33 ounces per gallon for Chiller Water or 50 to
150 ppm

500 to 1200 ppm for Carcass Spray	None stated

Poultry Processing Water	Soluble Concentrate, Ready to use Solution

21164-6

21164-8

21164-9

53345-19

53345-20

56485-4

74517-2

53345-21

74517-1

74119-1	None stated	3 ppm max	None stated

Poultry Drinking Water	Soluble Concentrate

74602-2	Add to water	5ppm for fouled water

0.5 to 1.0ppm for control	None stated

Poultry, swine, cattle and other livestock Drinking Water	Soluble
Concentrate

64449-1	Add to water	5ppm for fouled water

0.5 to 1.0ppm for control	None stated

Egg Room/  Hatching Area

Incubator Room

Tray Washing Room and Loading Platform	Soluble Concentrate

74602-2	High pressure sprayer	20 ppm for pre wash w/ sprayer

390 ppm to preclean floors

1,000 ppm treatment w/ fogger	None Stated

Egg Shells (Food Grade)	Soluble Concentrate

74602-2	Wet Thoroughly	5.0 ppm	Do not reuse solution

Chick Room, Chick Grading Box an Sexing room	Soluble Concentrate

74602-2	Fogger, Mop	1,000 ppm w/ fogger

390 ppm to mop floors	None Stated

Agricultural premises and equipment

Horticulture uses 

Work Area and Benches

	Soluble Concentrate

70060-6	Cloth, mop, sponge or sprayer	100 ppm	Do not Apply directly to
Plant Material

Horticulture uses

Pots and Flats	Soluble Concentrate

70060-6	Soak	100 ppm	Remove all loose soil and plant residue prior to
application

Horticulture uses

Cutting Tools	Soluble Concentrate

70060-6	Soak	100 ppm	None Stated

Horticulture uses

Bulbs

Soak	9 to 18 fl oz per gallon/ 253 ppm to 506 ppm	None Stated

Horticulture uses

Greenhouse Glass, Walkways and under Bench Areas	Soluble Concentrate

70060-6

	Spray	33 to 100 ppm	None Stated

Evaporative Coolers	Soluble Concentrate

70060-6	Add to water	100 ppm	None Stated

Food handling/ Storage establishments premises and equipment

Non-Porous, Food Contact, hard surface sanitizer	Soluble concentrate:

74986-1, 70060-19, 21164-3, 21164-8, 21164-9, 5382-46	Foamer, Dilution
device or spray	5ppm of activated available chlorine dioxide	None stated

Food Processing Plants

(Poultry, Meat, Fish) 

	Soluble Concentrate

74602-2, 21164-3	fogger	0.5 ppm	Ventilate for 15 minutes prior to
reentry

Food Processing Plants

(Poultry, Meat, Fish) 

Food Contact Surface Sanitizer	Soluble concentrate:

Reg:53345-14

53345-19

53345-20

69151-3

70060-6

9150-7

	1 minute contact time	50ppm- 1,000 ppm total available chlorine Dioxide

	Preclean and rinse equipment. Do not reuse solution. Do not rinse
treated surface

Food handling/ Storage establishments premises and equipment

Fruit and Vegetables	Soluble Concentrate

9150-8	Spray or dip	500 to 1200 ppm	Rinse with potable water after
treatment.



Dairies, Breweries and Bottling Plants

	Soluble Concentrate

74602-2

74602-1	Fogger	0.5 ppm	Ventilate for 15 minutes prior to reentry

Dairies, Breweries and Bottling Plants

Food Contact Surface Sanitizer	Soluble concentrate:

53345-14

53345-19

53345-20

9150-7

9150-8

21164-6

21164-8

21164-9

74602-2

5382-46

74517-1

53345-21

73139-1

	1 minute contact time	50ppm- 1,000 ppm total available chlorine Dioxide

	Preclean and rinse equipment. Do not reuse solution. Do not rinse
treated surface

Lube Additive for Moving Conveyors and Chains	Soluble concentrate: 
74602-3, 21164-3	Inject into distribution system

	10- 20 ppm	Preclean and sanitize all conveyor surfaces and associated
structures

Canning Retort and Pasteurizer Cooling Water	Soluble concentrate: 
70060-6, 74602-2, 70060-16, 53345-14, 9150-7, 9150-8,  46207-5, 5382-46

	Controlled Chemical Feed Pump 	0.1-5ppm	None stated

Food handling/ Storage establishments premises and equipment

Stainless Steel Transfer Lines, Hydrocoolers and Pasteurizers	Soluble
concentrate:

70060-6, 74602-2, 5382-46	Mix and fill lines and Equipment overnight

	20 ppm 	Preclean equipment or line thoroughly 

Process Water for Vegetable Rinses, Tanks Lines	70060-6, 5382-46
Chemical Feed Pump or injector system

	5 ppm	Preclean all tanks, flumes and lines with suitable detergent.

Fruit and Vegetable Rinse	Soluble concentrate:

45631-22, 45631-20, 74602-2, 45631-19, 53345-20, 56485-4, 45631-22,
69151-5, 9150-7, 9150-8, 21164-21, 45631-19, 5382-46

79814-3

	Immersion, spray	1/3 fl. to 1 gallon of water per 25 gallons of water

3-5 ppm	Prewash whole fruits and vegetables with clean potable water.

Ice Making Plants and Machinery

	Ready to use:

70060-13

	Hang or place the sachet in the ice chamber out of direct contact with
water or ice

	50 to 200 g sachet per 100 to 400 lbs per day	None stated

	Soluble concentrate: 5382-46	Chemical Feed Pump or Injector System

	20 ppm	None stated

Human Water Systems

Potable Drinking Water	Soluble concentrate:

53345-14

53345-19

53345-20

53345-22

69151-5

69151-3

70060-6

9150-7

9150-8

21164-6

21164-8

21164-9

21164-21

74602-2

5382-41

5382-42

5382-45

5382-46

74517-2

74517-1

53345-21

74602-1

79814-3

	Metering Pump

1 mg/ liter (1ppm) or less

1 gallon per 100,000 gallons of treated water	1 mg/ liter (1ppm) or less

1 gallon per 100,000 gallons of treated water	None Stated



None stated	5 ppm	None stated

	Ready to use:

70060-22

	Tablet	1 tablet per liter of water.  Four hour treatment time.	None
stated

Water Storage systems aboard Aircraft Boats, RV’s Off-shore Oil Rigs
Soluble concentrate:

74602-2

5382-46	Add to tank and lines	50 to 500 ppm available chlorine dioxide
None stated

Human Water Systems

Municipal Well Waters	Soluble concentrate:

53345-23

55050-1

55050-2

70060-6

46207-5

74602-2

5382-46

	None stated	1 ppm	None stated

Commercial, institutional and industrial premises and equipment

Non-Porous, Non-food Contact, hard surface sanitizer	Soluble
concentrate:

74986-1, 53345-13, 70060-19, 45631-15, 

	Dilution device or sprayer	100 ppm-200 ppm

	Odors on Pets, Litter Boxes, Carpets and Concrete Floors	Soluble
concentrate:

70060-6, 70060-4	Soak, Mop or rinse	For litter boxes: 625 – 650ppm

For carpets: 500 ppm

Concrete floors: 1250 ppm

Animal Baths: 80-100 ppm

	Avoid direct contact with animal’s eyes, nose and ears

Residential

Bathroom surfaces, shower stalls, curtains, laundry rooms, hampers and
other non specified surfaces for mold and mildew control.	Soluble
concentrate

74602-2	Spray, fog, pour, wipe	Dilute 13 fl. oz. solution as needed

5 minutes surface contact	After 30 minutes rinse with water

De-oderizer pouches for Refrigerators, Shoes, Gym Basements, Lockers,
Laundry Hampers, Automobiles, Boat Cabins, athletic bags, trash cans 
pet areas, etc.	Ready to use Solution , Impregnated Materials

9804-10

70060-12	Hang or place sachet (deodorizing pouch)	5 to 200 grams sachet
for use from 1 week to 2 months	None Stated.

Carpets	Ready to Use Powder

4822-512	Sprinkle on Carpet	2.5 oz per square yard.	Keep Children and
pets off treated areas during application and until area is vacuumed.

Medical premises and equipment

Hospitals, Laboratories and Institutions

Hard Non Porous surfaces (Tile floors, Walls and Ceilings and Stainless
Steel Cold Rooms)

	Soluble concentrate:

74602-2, 69151-1, 69151-5	Spray, Mop or sponge	Working Solution
containing 300 to 500 ppm available Chlorine Dioxide	Clean all surfaces
with a suitable detergent and rinse with water prior to disinfection.

Treatment of infectious medial waste (prior to disposal in a in a
conventional solid waste landfill)

	Soluble concentrate:

69972-1	Approved application system	None listed on label	None stated

Water Bath Incubator	Soluble concentrate:

74602-2, 70060-6	Pour solution into waterbath reservoir	Working Solution
containing 300 ppm available Chlorine Dioxide to disinfect

50 ppm for odor and slime control

	Clean reservoir with a suitable detergent and rinse with water prior to
disinfection

Sterilization of Spent Biologicals in Steam Autoclaves	Soluble
concentrate:

70060-6	Spray or pour directly into autoclave buckets

	Working Solution containing 1,000 ppm available Chlorine Dioxide	None
Stated

To Deodorize Animal Holding Rooms, Sick Rooms, Morgues and Work rooms
Soluble concentrate:

70060-6	Spray solution on to walls ceilings and floors	Working Solution
containing 1,000 ppm available Chlorine Dioxide	Rooms to deodorize
should be in a clean condition prior to autoclaving.

Swimming Pools

Swimming Pools	Tablet form, Ready to Use solution

70060-20	Tablet insert in hair and lint basket	1 tablet for  under
10,000 gallons

2 tablets for over 10,000 gallons

Apply every 3-4 weeks	Do not add this product through any automatic
dispensing device. Apply product when no persons are in the pool.

Industrial Processes and water systems

Waste water 

	Soluble concentrate:

53345-20, 55050-1

55050-2

56485-4

69151-4

69151-3

9150-7

10707-32

21164-6

21164-8

21164-9

21164-21

46207-5

5382-41

5382-43

5382-45

74119-1

74517-3

74517-2

53345-10

79814-3

53345-12

5382-42

74602-1	Batch load or meter	5.0 ppm to 100 ppm 

	None Stated



Industrial Processes and water systems

Water Cooling systems	Soluble concentrate:

53345-14

53345-19

53345-22

56485-4

69151-4

10707-32

46207-5

5382-46

	Batch load or meter	5.0 ppm to 100 ppm 

	None stated

Industrial process water	Soluble concentrate:

53345-20

9150-7

21164-8

53345-21

74602-1	Batch load or meter	5.0 ppm to 100 ppm 

	NIOSH/MSHA approved respirator required 

Water Based Cutting Oils	Soluble concentrate:

70060-6	Slug does system	32 oz to 10 gallons per million gallons of
cutting oil	None stated

Oil Wells : Secondary Recovery Operations	Soluble concentrate:

69151-3

68329-18

70060-6

10707-32

21164-3

5382-41

74602-3

	None Stated	5,000 ppm available chlorine dioxide	None stated

Oilfield Injection 	Soluble concentrate:

74602-1

79814-3

	Shock dosage	200-3000ppm	None stated

Industrial Processes and water systems

Recirculating Cooling Towers	Soluble concentrate:

74062-1

79814-3	Cooling tower drip pan	0.1 to 5.0 ppm

55.3 fl. oz per 1000 gallons of water for initial dosage

2.6 fl. oz per 100 gallons of water for subsequent dosage	None Stated

Once Through Water Cooling Systems	Soluble concentrate:

53345-14

53345-19

53345-20

69151-3

70060-6

9150-7

9150-8

1757-96

5382-41

5382-43

5382-45

74119-1

74517-2

53345-21

74602-1

79814-3

	Slug and Continuous 	Slug Dose: 5-25 ppm

Continuous Dose: 0.25 to 2.0 ppm	None Stated



Paper Mills	Soluble concentrate:

53345-22

56485-4

69151-4

69151-3

70060-6

74602-1

9150-7

9150-8

10707-32

21164-6

21164-8

21164-9

21164-21	None stated	4.5 gallons product per 100 tons of paper

.01 – 5.0 ppm (3.2 – 12.8 fluid ounces per 1,000 gallons of water
None stated

Industrial Processes and water systems

Paper Mills	Soluble concentrate:

46207-5

5382-41

5382-42

5382-43

5382-45

74119-1

74517-2

53345-21

74655-2

	None stated	4.5 gallons product per 100 tons of paper

1.25 – 5.0 ppm (3.2 – 12.8 fluid ounces per 1,000 gallons of water
None stated



  SEQ CHAPTER \h \r 1 APPENDIX B:  Chlorine dioxide and Sodium
Chlorite* (Case 4023)

Appendix B lists the generic (not product specific) data requirements
which support the re-registration of Chlorine Dioxide and Sodium
Chlorite.  These requirements apply to Chlorine Dioxide and Sodium
Chlorite in all products, including data requirements for which a
technical grade active ingredient is the test substance.  The data table
is organized in the following formats:

1.	Data Requirement (Columns 1 and 2).  The data requirements are listed
by Guideline Number.  The first column lists the new Part 158 Guideline
numbers, and the second column lists the old Part 158 Guideline numbers.
Each Guideline Number has an associated test protocol set forth in the
Pesticide Assessment Guidance, which are available on the EPA website.

Guideline Description (Column 3). Identifies the guideline type.  

3.	Use Pattern (Column 4).  This column indicates the standard
Antimicrobial Division use patterns categories for which the generic
(not product specific) data requirements apply. The number designations
are used in Appendix B.    

			

	(1) Agricultural premises and equipment

	(2) Food handling/ storage establishments’ premises and equipment

	(3) Commercial, institutional and industrial premises and equipment

	(4) Residential and public access premises

	(5) Medical premises and equipment

	(6) Human water systems

	(7) Materials preservatives

	(8) Industrial processes and water systems

	(9) Antifouling coatings

	(10) Wood preservatives

	(11) Swimming pools

	(12) Aquatic areas

	

3.	Bibliographic Citation (Column 5).  If the Agency has data in its
files to support a specific generic Guideline requirement, this column
will identity each study by a “Master Record Identification (MRID)
number. The listed studies are considered “valid” and acceptable for
satisfying the Guideline requirement. Refer to the Bibliography appendix
for a complete citation of each study.	



DATA REQUIREMENT	CITATION(S)

New Guideline Number	Old Guideline Number	Study Title	Use Pattern	MRID
Number

PRODUCT CHEMISTRY 

830.1550	61-1	Product Identity and Composition	1-4, 5, 8, 11	41467601,
41467602

830.1600 830.1620

830.1650	61-2a	Starting Materials and Manufacturing Process	1-4, 5, 8,
11	41467601, 41467602

830.1670	61-2b	Formation of Impurities	1-4, 5, 8, 11	41467601, 41467602

830.1700	62-1	Preliminary Analysis	1-4,, 5, 8, 11	41467601, 41467602

830.1750	62-2	Certification of Limits	1-4, 5, 8, 11	41467601, 41467602

830.1800	62-3   	Analytical Method	1-4, 5, 8, 11	41467601, 41467602

830.6302	63-2	Color	1-4, 5, 8, 11

	41467601, 41467602

830.6303	63-3	Physical State	1-4, 5, 8, 11	41467601, 41467602

830.6304	63-4	Odor	1-4, 5, 8, 11	41467601, 41467602

830.7200	63-5	Melting Point	1-4, 5, 8, 11	41467601, 41467602

830.7220	63-6	Boiling Point	1-4, 5, 8, 11	41467601, 41467602

830.7300	63-7	Density	1-4, 5, 8, 11	41467601, 41467602

830.7840

830.7860	63-8	Solubility	1-4, 5, 8, 11	41467601, 41467602

830.7950	63-9	Vapor Pressure	1-4, 5, 8, 11	41467601, 41467602

830.7550

830.7560

830.7570	63-11	Partition Coefficient (Octanol/Water)	1,4, 5, 8, 11
41467601, 41467602

830.7000	63-12	pH	1-4, 5, 8, 11	41467601, 41467602

830.6313	63-13	Stability	1-4, 5, 8, 11	41467601, 41467602

830.6314	63-14	Oxidizing/Reducing Action	1-4, 5, 8, 11	41467601,
41467602

830.6315	63-15	Flammability	1-4, 5, 8, 11	41467601, 41467602

830.6316	63-16	Explodability	1-4, 5, 8, 11	41467601, 41467602

830.6317	63-17	Storage Stability	1-4, 5, 8, 11	41467601, 41467602

830.6319	63-19   	Miscibility	1-4, 5, 8, 11	41467601, 41467602

ECOLOGICAL EFFECTS

850.1300	72-4	Fish early life-stage testing-freshwater

Data gap

850.1400	72-4b	Invertebrate life-cycle testing - freshwater

Data gap

850.4225	123-1	Seedling emergence dose-response in rice

Data gap

850.4250	123-1	Vegetative vigor dose-response in rice

Data gap

850.4400	123-2	Aquatic vascular plant dose-response toxicity- Lemna sp.

Data gap

850.5400	123-2	Acute algal dose-response toxicity - 4 species

Data gap (only one species tested-MRID 41880403)

850.2100	71-1	Avian Acute Oral Toxicity Test (Quail/Duck)

ACC259373,ACC257341, ACC253378, MRID 31610, ACC254177, ACC252854

850.1075	72-1	Fish Acute Toxicity – Freshwater (Rainbow Trout)

MRID94068007, ACC254181, ACC254180, ACC252854, ACC245697, ACC69810,
ACC253379, MRID94068006

850.1010	72-2	Acute Aquatic Invertebrate Toxicity

MRID146162, MRID141149, MRID131350, ACC254182, MRID94068009



TOXICOLOGY*

870.1100	81-1	Acute Oral - Rat

MRID 43558601

870.1200	81-2	Acute Dermal - Rabbit

MRID 40168704

870.1300	81-3	Acute Inhalation - Rat

MRID 42484101

870.2400	81-4	Primary Eye Irritation - Rabbit

MRID 43441903

870.2500	81-5	Primary Dermal Irritation - Rabbit

MRID40168704

870.2600	81-6	Dermal Sensitization

Data gap

870.3100	82-1a	90-Day Oral (gavage) -Rat

MRID 42301601

870.3465	82-4	28/90-Day Inhalation - Rat

Open literature

870.3700	83-3	Developmental Toxicity -Rat

Open literature

870.3700	83-3	Developmental Toxicity - Rabbit

MRID 41715701

870.3800	83-4	Two-generation Reproduction - Rat

MRID 45358901

870.5265	84-2	Bacterial Reverse Mutation Assay

Open literature

870.5300	84-2	Detection of gene mutations in somatic cells

ACC265867

870.5385	84-2	Micronucleus Assay

Open literature

870.4200	83-2	Carcinogenicity

Data gap



* Databases for chlorine dioxide and sodium chlorite were used
interchangeably.  

Appendix C.  Technical Support Documents  XE "VI. Appendices:C.
Technical Support Documents"  

	Additional documentation in support of this RED is maintained in the
OPP docket located in Room S-4400, One Potomac Yard (South Building),
2777 S. Crystal Drive, Arlington, VA 22202, and is open Monday through
Friday, excluding Federal holidays, from 8:30 a.m. to 4:00 p.m.

	The docket initially contained the draft risk assessments and related
documents as of April 28, 2004.  Sixty days later the first public
comment period closed.  The EPA then considered all comments and revised
the risk assessments.

	All documents, in hard copy form, may be viewed in the OPP docket room
or downloaded or viewed via the Internet at the following site:  
HYPERLINK "http://www.regulations.gov"  http://www.regulations.gov ,
docket ID # EPA-HQ-OPP-2006-0328.

	These documents include:

Chlorine Dioxide Draft Risk Assessment, 4/6/2006.

Chlorine Dioxide Toxicology Disciplinary Chapter, 4/5/2006.

Chlorine Dioxide Occupational and Residential Exposure Assessment,
4/5/2006.

Chlorine Dioxide Environmental Fate and Transport Assessment, 4/5/2006.

Chlorine Dioxide Product Chemistry Chapter, 4/5/2006.

Chlorine Dioxide Dietary Exposure Assessment, 4/6/2006.

Chlorine Dioxide Environmental Hazard and Risk Assessment, 4/6/2006.

Chlorine Dioxide Incident Reports, 2/23/2006.

Chlorine Dioxide Environmental Modeling Chapter, 6/28/2005.



Appendix D.	Citations Considered to be Part of the Data Base Supporting
the Reregistration Decision (Bibliography)  XE "VI. Appendices:D.
Bibliography Citations"  

GUIDE TO APPENDIX D		

				

1.	CONTENTS OF BIBLIOGRAPHY.  This bibliography contains citations of
all studies considered relevant by EPA in arriving at the positions and
conclusions stated elsewhere in the Chlorine Dioxide Reregistration
Eligibility Document.  Primary sources for studies in this bibliography
have been the body of data submitted to EPA and its predecessor agencies
in support of past regulatory decisions.  Selections from other sources
including the published literature, in those instances where they have
been considered, are included.

2.	UNITS OF ENTRY.  The unit of entry in this bibliography is called a
“study.”  In the case of published materials, this corresponds
closely to an article.  In the case of unpublished materials submitted
to the Agency, the Agency has sought to identify documents at a level
parallel to the published article from within the typically larger
volumes in which they were submitted.  The resulting “studies”
generally have a distinct title (or at least a single subject), can
stand alone for purposes of review and can be described with a
conventional bibliographic citation.  The Agency has also attempted to
unite basic documents and commentaries upon them, treating them as a
single study.

3.	IDENTIFICATION OF ENTRIES.  The entries in this bibliography are
sorted numerically by Master Record Identifier, or “MRID” number. 
This number is unique to the citation, and should be used whenever a
specific reference is required.  It is not related to the six-digit
“Accession Number” which has been used to identify volumes of
submitted studies (see paragraph 4(d)(4) below for further explanation).
 In a few cases, entries added to the bibliography late in the review
may be preceded by a nine character temporary identifier.  These entries
are listed after all MRID entries.  This temporary identifying number is
also to be used whenever specific reference is needed.

4.	FORM OF ENTRY.  In addition to the Master Record Identifier (MRID),
each entry consists of a citation containing standard elements followed,
in the case of material submitted to EPA, by a description of the
earliest known submission.  Bibliographic conventions used reflect the
standard of the American National Standards Institute (ANSI), expanded
to provide for certain special needs.

a.	Author.  Whenever the author could confidently be identified, the
Agency has chosen to show a personal author.  When no individual was
identified, the Agency has shown an identifiable laboratory or testing
facility as the author.  When no author or laboratory could be
identified, the Agency has shown the first submitter as the author.

b.	Document date.  The date of the study is taken directly from the
document.  When the date is followed by a question mark, the
bibliographer has deduced the date from the evidence contained in the
document.  When the date appears as (1999), the Agency was unable to
determine or estimate the date of the document.

c.	Title.  In some cases, it has been necessary for the Agency
bibliographers to create or enhance a document title.  Any such
editorial insertions are contained between square brackets.

d.	Trailing parentheses.  For studies submitted to the Agency in the
past, the trailing parentheses include (in addition to any
self-explanatory text) the following elements describing the earliest
known submission:

(1)	Submission date.  The date of the earliest known submission appears
immediately following the word “received.”

(2)	Administrative number.  The next element immediately following the
word “under” is the registration number, experimental use permit
number, petition number, or other administrative number associated with
the earliest known submission.

(3)	Submitter.  The third element is the submitter.  When authorship is
defaulted to the submitter, this element is omitted.

(4)	Volume Identification (Accession Numbers).  The final element in the
trailing parentheses identifies the EPA accession number of the volume
in which the original submission of the study appears.  The six-digit
accession number follows the symbol “CDL,” which stands for
“Company Data Library.”  This accession number is in turn followed
by an alphabetic suffix which shows the relative position of the study
within the volume.

MRID Studies

MRID #		Citation

31610	Fletcher, D. 1973.  Acute Oral Toxicity Study with Sodium Chlorite
in Bobwhite Quail.  Unpublished Data.  Conducted by Industrial BIO-TEST
Laboratories, Inc. for Olin Corporation.

69809	1978.  Acute Toxicity of Sodium Chlorite to Bluegill (Lepomis
macrochirus).  Unpublished Data.  Conducted by EG&G, Bionomics, Aquatic
Toxicology Laboratory for Olin Chemicals.

69810	1979.  Acute Toxicity of Sodium Chlorite to Rainbow Trout (Salmo
gairdneri).  Unpublished Data.  Conducted by EG&G, Bionomics, Aquatic
Toxicology Laboratory for Olin Chemicals.

80194	Sousa, J.V.  1981.  Acute Toxicity of Sodium Chlorite to
Bluegill(Lepomis macrochirus).  Unpublished Data.  Conducted by EG&G,
Bionomics for Olin Chemicals.

118007  	Sousa, J.V. and D.C. Surprenant.  1984.  Acute Toxicity of
AC-66 to Rainbow Trout (Salmo gairdneri).  Unpublished Data.  Conducted
by Springborn Bionomics, Inc. for Calgon Corporation.

130649  	Fink, R.  1977.  Eight-day Dietary LC50 - Bobwhite Quail –
Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife
International, Ltd. for Olin Corporation.

130650 	Fink, R.  1977.  Eight-day Dietary LC50 – Mallard Duck –
Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife
International, Ltd. for Olin Corporation.

	

131350	Vilkas, A.G.  1976.  Acute Toxicity of Textone to the Water Flea
Daphnia magna Strauss.  Unpublished Data.  Conducted by Aquatic
Environmental Sciences for Olin Corporation. 

131351	Sleight III, B.H.  1971.  Acute Toxicity of Sodium Chlorite to
Bluegill (Lepomis macrochirus) and Rainbow Trout (Salmo gairdneri). 
Unpublished Data.  Conducted by Bionomics, Inc.

 

141149	Hoberg, J.R. and D.C. Surprenant.  1984.  Acute Toxicity of AC-66
to Daphnids (Daphnia magna).  Unpublished Data.  Conducted by Springborn
Bionomics, Inc. for Calgon Corporation.

141151	Fletcher, D.  1984.  8-Day Dietary LC50 Study with Sodium
Chlorite in Bobwhite Quail.  Unpublished Data.  Conducted by Bio-Life
Associates, Ltd. for Calgon Corporation.

141152	Fletcher, D.  1984.  Acute Oral Toxicity Study with Sodium
Chlorite in Bobwhite Quail.  Unpublished Data.  Conducted by Bio-Life
Associates, Ltd. for Calgon Corporation.

142327  	McMillen, C.  1984.  Static Bioassay on Sodium Chlorite to
Rainbow Trout and Bluegill Sunfish.  Unpublished Data.  Conducted by
Environmental Research Group, Inc. for Rio Linda Chemical Company, Inc.

143970	Fletcher, D.  1984.  8-Day Dietary LC50 Study with Sodium
Chlorite in Mallard Ducklings.  Unpublished Data.  Conducted by Bio-Life
Associates, Ltd. for Calgon Corporation.

144730	Robaidek and Johnson, 1985. Avian Single-dose Oral LD50: Bob
White Quail (Colinus virginianus).  Unpublished Data.   Conducted by
Hazleton Laboratories America, Inc. for Rio Linda Chemical Company.

145405 	Beavers, 1984.  An Acute Oral Toxicity Study in the Mallard with
Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife
International, Ltd. for TR America Chemicals, Inc.

145406 	Beavers, 1984.  An Acute Oral Toxicity Study in the Bobwhite
with Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife
International, Ltd. for TR America Chemicals, Inc.

145407  	Beavers, 1984.  A Dietary LC50 Study in the Mallard Duck with
Sodium Chlorite.  Unpublished Data.  Conducted by Wildlife
International, Ltd. for TR America Chemicals, Inc.

145408 	Beavers, 1984.  A Dietary LC50 Study in the Bobwhite with Sodium
Chlorite.  Unpublished Data.  Conducted by Wildlife International, Ltd.
for TR America Chemicals, Inc.

145409  	Larkin, J.  1984.  The Acute Toxicity of Sodium Chlorite to
Rainbow Trout (Salmo gairdneri).  Unpublished Data.  Conducted by
Biospherics Incorporated for TR America Chemicals, Inc.

145510	Larkin, J.  1984.  The Acute Toxicity of Sodium Chlorite to
Bluegill Sunfish (Lepomis macrochirus).  Unpublished Data.  Conducted by
Biospherics Incorporated for TR America Chemicals, Inc.  

145411	Larkin, J.  1984.  Acute Toxicity of Sodium Chlorite to Daphnia
magna Strauss.  Unpublished Data.  Conducted by Biospherics Incorporated
for TR America Chemicals, Inc.

146162	Barrows, 1984.  The Acute Toxicity of Sodium Chlorite Technical
to the Water Flea, Daphnia magna in a Static Test System.  Unpublished
Data.  Conducted by Biospherics Incorporated for Degussa Corporation.   
  

148727  	Robaidek, E.  1985.  Avian Single-Dose Oral LD50 Bobwhite
Quail.  Unpublished Data.  Conducted by Hazleton Laboratories America,
Inc. for Degussa Corporation.

161875	1984.  96-Hour LC50 in Juvenile Rainbow Trout.  Unpublished Data.
 Conducted by Microbiological and Biochemical Assay Laboratories for
Magna Corporation.

161876	1984.  48-Hour LC50 in Daphnia magna.  Unpublished Data. 
Conducted by Microbiological and Biochemical Assay Laboratories for
Magna Corporation.

161877  	1984.  Avian Dietary LC50 in Bob White Quail.  Unpublished
Data.  Conducted by Microbiological and Biochemical Assay Laboratories
for Magna Corporation.

161878	1983.  Avian Dietary LC50 in Mallard Ducks.  Unpublished Data. 
Conducted by Microbiological and Biochemical Assay Laboratories for
Magna Corporation.

161879	1984.  Avian Single-Dose Oral LD50 in Bobwhite Quail. 
Unpublished Data.  Conducted by Microbiological and Biochemical Assay
Laboratories for Magna Corporation.

164863	Cifone, M. 1994.  Mutagenicity Evaluation of Chlorine Dioxide in
the Mouse Lymphoma Foreword Mutation Assay.  Litton Bionetics,
Kensington, MD, LBI Project No. 20989, March 1984.

40168704  	1985.  Acute Dermal LD50 on Rabbit – Sodium Chlorite
Powder, Lot #110984-15.  Gibraltar Biological Lab, Inc. (Fairfield, NJ),
Internaltional Dioxcide, Inc. Study Number GBL 024065, April 23, 1985.

41715701	Irvine, Lorraine F.  Sodium Chlorite:  Rabbit Teratology Study
(Drinking Water Administration).  Toxicol. Labs, Ltd., Ledbury, UK,
Study Number CMA/3/R, September 21, 1990.



41843101  	Backus, P., K.E. Crosby and L.J. Powers.  1990.  Effect of
Sodium Chlorite on Vegetative Vigor of Plants (Tier I).  Unpublished
Data.  Conducted by Ricerca, Inc. for the Sodium Chlorite Reregistration
Task Force.

41843102  	Backus, P., K.E. Crosby and L.J. Powers.  1990.  Effect of
Sodium Chlorite on Seed Germination/Seedling Emergence (Tier I). 
Unpublished Data.  Conducted by Ricerca, Inc. for the Sodium Chlorite
Reregistration Task Force.

41880403 	Ward, T.J. and R.L. Boeri.  1991.  Static Acute Toxicity of
Sodium Chlorite to the Freshwater Alga, Selenastrum capricornutum. 
Unpublished Data.  Conducted by EnviroSystems Division, Resource
Analysis, Inc. for the Sodium Chlorite Reregistration Task Force.

41919701 	Rat Acute Oral Toxicity:  Oxine – New Powerful Bacteriostat
and Sanitizer.  Stillmeadow, Inc., Houston, TX, Lab. Project No.
3347-84, August 3, 1984.

41919702 	Rat Acute Dermal Toxicity:  Oxine – New Powerful
Bacteriostat and Sanitizer.  Stillmeadow, Inc., Houston, TX, Lab.
Project No. 3348-84, July 11, 1984.

41919703	 Rat Acute Inhalation Toxicity:  Oxine
–Bacteriostat/Deodorizer (AKA Purogene).  Stillmeadow, Inc., Houston,
TX, Lab. Project No. 4777-87, June 10, 1987.

41919704 	Rabbit Eye Acute Irritation:  Oxine- New Powerful Bacteriostat
and Sanitizer.  Stillmeadow, Inc., Houston, TX, Lab. Project No.
3349-84, June 26, 1984.

41919705 	Rabbit Skin Irritation:  Oxine – New Powerful Bacteriostat
and Sanitizer.  Stillmeadow, Inc., Houston, TX, Lab. Project No.
3350-84, June 26, 1984.

42301601 	Ridgway, P.(1992) 13 Week Oral(Gavage) Toxicity Study in the
Rat: Lab Project Number:CMA/13/R:CD-6.0-Tox.Unpublished study prepared
by Toxicol Labs Ltd for the CMA/Chlorine Dioxide Panel.329p.

42587501  	Popendorf, W.; Selim, M.; Kross, B. 1992. Chemical
Manufacturers Association Antimicrobial Exposure Assessment Study:
Second Replacement to MRID 41761201: Lab Project Number: Q626.
Unpublished study prepared by The University of Iowa.

42484101	Acute Inhalation Toxicity Evaluation in Rats.  International
Research and Development Corporation (IRDC), Mattawan, MI.  Lab. Project
No. 632-001, August 14, 1992.

43259401	Yurk, J.J. and M.A. Overman.  1994.  Acute Toxicity of Sodium
Chlorite to the Sheepshead Minnow (Cyprinodon variegatus).  Conducted by
Environmental Science & Engineering, Inc. for the Chemical Manufacturers
Association.

43259402 	Yurk, J.J. and M.A. Overman.  1994.  Acute Toxicity of Sodium
Chlorite to Mysid Shrimp.  Conducted by Environmental Science &
Engineering, Inc. for the Chemical Manufacturers Association.

43259403 	Yurk, J.J. and M.A. Overman.  1994.  Effect of Sodium Chlorite
on New Shell Growth in Eastern Oyster (Crassostrea virginica). 
Conducted by Environmental Science & Engineering, Inc. for the Chemical
Manufacturers Association.

43441901 	Acute Oral Toxicity Study in Rats.  Stillmeadow, Inc., Sugar
Land, TX, Lab. Project No. 1439-94, October 26, 1994.

43441902 	Acute Dermal Toxicity Study in Rabbits.  Stillmeadow, Inc.,
Sugar Land, TX, Lab. Project No. 1440-94, October 10, 1994.

43441903  	Primary Eye Irritation Study in Rabbits.  Stillmeadow, Inc.,
Sugar Land, TX, Lab. Project No. 1441-94, October 11, 1994.

43503201 	Irritant Effects of Duozon 100-1 As a concentration of 0.3 ppm
relating to chlorine dioxide (CLO2) on rabbit skin.  Pharmatox,
Landkreis, Hannover, Germany, Lab. Project No. Not Available, July, 1994

43558601	Abdel-Rahman, et al., “Toxicity of Alcide,” published in J.
Appl. Toxicol. 2(3): 160-164, 1982.

43558602 	Dalhamn, T., “Chlorine Dioxide:  Toxicity in Animal
Experiments and Industrial Risks,” published in A.M.A. Arch. Indust.
Hlth. 15(2): 101-107, 1957.

45358901	Bailey, G. (1996) Sodium Chlorite: Drinking Water Rat
Two--Generation Reproductive Toxicity Study: Amended Final Report: Lab
Project Number: CMA/17/R. Unpublished study prepared by Quintiles
England Ltd. 2120 p

46919601 	Kennedy, J. (2002) Investigation of Potential Chemical
Exposure From HVAC Duct Sanitation Using Chlorine Dioxide Based Produce
Oxine (AD): Final Study Report. Project Number: BCI/0001. Unpublished
study prepared by Bio-Cide International Inc. 19 p.

46919602 	Harrington, R. (2002) Toxicological Assessment of Oxine During
In-Home HVAC Treatment: Final Study Report. Project Number: BCI 0002.
Unpublished study prepared by Bio-Cide International Inc. 29 p.

94068005	Johnson, G.  1984.  Avian Dietary LC50 Bobwhite Quail (Colinus
virginianus).  Unpublished Data.  Conducted by Hazleton Laboratories
America, Inc. for Degussa Corporation.

94068006 	Sousa and Surprenant, 1984.  Acute Toxicity of A-66 (Technical
Sodium Chlorite) to Bluegill (Lepomis macrochirus).  Unpublished Data. 
Conducted by Springborn Binomics, Inc for Calgon Corporation.

94068007 	Barrows, B. 1984.  The Acute Toxicity of Sodium Chlorite
Technical to the Rainbow Trout, Salmo gairdneri, in a Static Test
System.  Unpublished Data.  Conducted by Biospherics Incorporated for
Degussa Corporation.

94068008.	Johnson, G.  1984.  Avian Dietary LC50 Mallard Duck (Anas
platyrhynchos).  Unpublished Data.  Conducted by Hazleton Laboratories
America, Inc. for Degussa Corporation.

94068009	Nachrord, S.  1984.  Daphnia LC50 Bioassay.  Unpublished Data. 
Conducted by Anater Tesconi Circle for Rio Linda Chemical Company, Inc.

Accession Studies

Accession #		Citation

252854  	1983.  96-Hour LC50 in Bluegill Perch.  Unpublished Data. 
Conducted by Microbiological and Biochemical Assay Laboratories for
Magna Corporation.

Open Literature

Citation

Dalhamn, T. (1957): Chlorine Dioxide: Toxicity in Animal Experiments and
Industrial Risks. Arch. Ind. Health 15: 101-107. 

Daniel, F.B., et al. (1990): Comparative subchronic toxicity studies of
three disinfectants.  J Am Water Works Assoc 82:61-69.

Haag, H.B. (1949): The effect on rats of chronic administration of
sodium chlorite and chlorine dioxide in the drinking water.  Report to
the Mathieson Alkali Works from H.B. Haag of the Medical College of
Virginia.  February 7, 1949. 

Harrington, R.M., et al. (1995a): Subchronic toxicity of sodium chlorite
in the rat.  J Am Coll Toxicol 14:21-33.

Harrington, R.M., et al. (1995b) Developmental toxicity of sodium
chlorite in the rabbit.  J Am Coll Toxicol 14:109-118.

Kurokawa, Y., et al. (1984): Studies on the promoting and complete
carcinogenic activities of some oxidizing chemicals in skin
carcinogenesis.  Cancer Lett 24:299-304.

Meier, J.R., et al. (1985): Evaluation of chemicals used for drinking
water disinfection for production of chromosomal damage and sperm-head
abnormalities in mice.  Environ Mutagen 7:201-211. 

Miller, R.G., et al. (1986): Results of toxicological testing of
Jefferson Parish pilot plant samples.  Environ Health Perspect
69:129-139. 

Mobley, S.A., et al. (1990): Chlorine dioxide depresses T3 uptake and
delays development of locomotor activity in young rats. In: Jolley, RL,
et al., eds. Water chlorination: chemistry, environmental impact and
health effects, vol. 6. Chelsea, MI: Lewis Publications, pp. 347-358.

Moore, G.S. and E.J. Calabrese (1982): Toxicological effects of chlorite
in the mouse.  Environ Health Perspect 46:31-37.

Orme, J., et al. (1985): Effects of chlorine dioxide on thyroid function
in neonatal rats. J Toxicol Environ Health 15:315-322.

Paulet G and S. Desbrousses (1970): On the action of ClO2 at low
concentrations on laboratory animals.  Arch Mal Prof 31:97-106.

Paulet G and S. Desbrousses (1972): On the toxicology of chlorine
dioxide.  Arch Mal Prof 33:59-61.

Paulet G and S. Desbrousses (1974): Action of a discontinuous exposure
to chlorine dioxide (ClO2) on the rat.  Arch Mal Prof 35:797-804.

Robinson, M; Bull, RJ; Schmaer, M; Long, RF. (1986) Epidermal
hyperplasia in the mouse skin following treatment with alternate
drinking water disinfectants. Environ Health Perspect 69:293-300.

Website References

Citation

FDA, 2003a.  “Guidance For Industry: Preparation of Food Contact
Notifications and Food Additive Petitions for Food Contact Substances:
Chemistry Recommendations.  Final Guidance.”  US Food and Drug
Administration.  April, 2003.   HYPERLINK
http://www.cfsan.fda.gov/~dms/opa2pmnc.html.
http://www.cfsan.fda.gov/~dms/opa2pmnc.html.   Last accessed June 9,
2003.

FDA, 2003b.  “Sanitizing Solutions:	Chemistry Guidelines for Food
Additive Petitions.”  US Food and Drug Administration.  January, 1993.
   HYPERLINK http://www.cfsan.fda.gov/~dms/opa-cg3a.html.
http://www.cfsan.fda.gov/~dms/opa-cg3a.html.   Last accessed June 9,
2003.

USEPA, 1999.  “Available Information on Assessing Exposure from
Pesticides, A User’s Guide.”   US Environmental Protection Agency,
Office of Pesticide Programs.  June 21, 1999.    HYPERLINK
http://www.epa.gov/fedrgstr/EPA-PEST/2000/July/Day-12/6061.pdf
http://www.epa.gov/fedrgstr/EPA-PEST/2000/July/Day-12/6061.pdf.  Last
accessed June 9, 2003.

USEPA, 2001a.  “General Principles for Performing Aggregate Exposure
and Risk Assessments.” US Environmental Protection Agency, Office of
Pesticide Programs.  November 28, 2001.    HYPERLINK
http://www.epa.gov/pesticides/trac/science/aggregate.pdf.
http://www.epa.gov/pesticides/trac/science/aggregate.pdf. 

USEPA, 2004. Overview of the Ecological Risk Assessment Process in the
Office of Pesticide Programs U.S. Environmental Protection Agency -
Endangered and Threatened Species Effects Determinations, Appendix A,
Section IIB, pg.81.  US Environmental Protection Agency.  January 24,
2004. 
http://www.epa.gov/oppfead1/endanger/consultation/ecorisk-overview.pdf.

Other Supporting Documents

Citation

US EPA.  1997a.  Standard Operating Procedures (SOPs) for Residential
Exposure Assessments.  Contract No. 68-W6-0030.  Prepared by the
Residential Exposure Assessment Work Group.  Office of Pesticide
Programs, Health Effects Division and Versar.  July 1997.

US EPA.  1997b.  Exposure Factors Handbook.  National Center for
Environmental Assessment, Office of Research and Development.

US EPA.  1997c.  Surrogate Exposure Guide: Estimates of Worker Exposure
from the Pesticide Handler Exposure Database, Version 1.1.  May 1997.

US EPA.  2000.  Standard Operating Procedures (SOPs) for Residential
Exposure Assessments.  Office of Pesticide Programs, Health Effects
Division.  April 2000.

US EPA 2001b.  Review of a Health Risk Assessment for PHMB (Vantocil IB)
used on 100% Cotton Textile Application - Systemic Toxicity by an Infant
Sucking Textile.  Memorandum for Siroos Mostaghimi, Ph.D. to Adam
Heyward.  January 3, 2001. 

Versar. 2003.  User's Manual Swimmer Exposure Assessment Model
(SWIMODEL) Version 3.0. Prepared for the US EPA Antimicrobials Division.
 November 2003.

Appendix E. Generic Data Call-In

The Agency intends to issue a Generic Data Call-In at a later date.  See
Chapter V of the Chlorine Dioxide RED for a list of studies that the
Agency plans to require.  

  XE "VI. Appendices:E. Generic Data Call-In"  

Appendix F. Product Specific Data Call-In

The Agency intends to issue a Product Specific Data Call-In at a later
date.

Appendix G.  Batching of Chlorine Dioxide and Sodium Chlorite Products
for Meeting Acute Toxicity Data Requirements for Reregistration

The Agency intends to complete batching at a later date.



Appendix H.  List of All Registrants Sent the Data Call-In

A list of registrants sent the data call-in will be posted at a later
date. 

 Appendix I.  	List of Available Related Documents and Electronically
Available Forms  XE "VI. Appendices:I. List of Available Related
Documents and Electronically Available Forms"  

Pesticide Registration Forms are available at the following EPA internet
site:

    HYPERLINK "http://www.epa.gov/opprd001/forms/" 
http://www.epa.gov/opprd001/forms/ 	.

Pesticide Registration Forms (These forms are in PDF format and require
the Acrobat reader) 

Instructions

1.	Print out and complete the forms.  (Note: Form numbers that are
bolded can be filled out on your computer then printed.)

2.	The completed form(s) should be submitted in hardcopy in accord with
the existing policy.  

3.	Mail the forms, along with any additional documents necessary to
comply with EPA regulations covering your request, to the address below
for the Document Processing Desk.

DO NOT fax or e-mail any form containing ‘Confidential Business
Information’ or ‘Sensitive Information.’

If you have any problems accessing these forms, please contact Nicole
Williams at (703) 308-5551 or by e-mail at   HYPERLINK
"mailto:williams.nicole@epamail.epa.gov" 
williams.nicole@epamail.epa.gov .

The following Agency Pesticide Registration Forms are currently
available via the internet at the following locations:

8570-1	 Application for Pesticide Registration/Amendment	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-1.pdf" 
http://www.epa.gov/opprd001/forms/8570-1.pdf 

8570-4	Confidential Statement of Formula	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-4.pdf" 
http://www.epa.gov/opprd001/forms/8570-4.pdf 

8570-5	Notice of Supplemental Registration of Distribution of a
Registered Pesticide Product 	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-5.pdf" 
http://www.epa.gov/opprd001/forms/8570-5.pdf 



8570-17	 Application for an Experimental Use Permit	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-17.pdf" 
http://www.epa.gov/opprd001/forms/8570-17.pdf 

8570-25	 Application for/Notification of State Registration of a
Pesticide To Meet a Special Local Need 	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-25.pdf" 
http://www.epa.gov/opprd001/forms/8570-25.pdf 



8570-27	 Formulator’s Exemption Statement	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-27.pdf" 
http://www.epa.gov/opprd001/forms/8570-27.pdf 

8570-28	 Certification of Compliance with Data Gap Procedures 	   
HYPERLINK "http://www.epa.gov/opprd001/forms/8570-28.pdf" 
http://www.epa.gov/opprd001/forms/8570-28.pdf 



8570-30	 Pesticide Registration Maintenance Fee Filing 	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-30.pdf" 
http://www.epa.gov/opprd001/forms/8570-30.pdf 

8570-32	 Certification of Attempt to Enter into an Agreement with other
Registrants for Development of Data 	    HYPERLINK
"http://www.epa.gov/opprd001/forms/8570-32.pdf" 
http://www.epa.gov/opprd001/forms/8570-32.pdf 

8570-34	 Certification with Respect to Citations of Data (in PR Notice
98-5)	    HYPERLINK "http://www.epa.gov/opppmsd1/PR_Notices/pr98-5.pdf" 
http://www.epa.gov/opppmsd1/PR_Notices/pr98-5.pdf 

8570-35	Data Matrix  (in PR Notice 98-5)	    HYPERLINK
"http://www.epa.gov/opppmsd1/PR_Notices/pr98-5.pdf" 
http://www.epa.gov/opppmsd1/PR_Notices/pr98-5.pdf 

8570-36	Summary of the Physical/Chemical Properties  (in PR Notice 98-1)
    HYPERLINK "http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf" 
http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf 

8570-37	 Self-Certification Statement for the Physical/Chemical
Properties  (in PR Notice 98-1)	    HYPERLINK
"http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf" 
http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf 

Pesticide Registration Kit	

    HYPERLINK "http://www.epa.gov" 
www.epa.gov/pesticides/registrationkit/ .

Dear Registrant:

	For your convenience, we have assembled an online registration kit that
contains the following pertinent forms and information needed to
register a pesticide product with the U.S.  Environmental Protection
Agency’s Office of Pesticide Programs (OPP):

1.	The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and
the Federal Food, Drug and Cosmetic Act (FFDCA) as Amended by the Food
Quality Protection Act (FQPA) of 1996.  

	2.	Pesticide Registration (PR) Notices 

		a.	83-3 Label Improvement Program—Storage and Disposal Statements 

		b.	84-1 Clarification of Label Improvement Program 

		c.	86-5 Standard Format for Data Submitted under FIFRA 

d.	87-1 Label Improvement Program for Pesticides Applied through
Irrigation Systems (Chemigation) 

		e.	87-6 Inert Ingredients in Pesticide Products Policy Statement 

		

f.	90-1 Inert Ingredients in Pesticide Products; Revised Policy
Statement 

		

g.	95-2 Notifications, Non-notifications, and Minor Formulation
Amendments 

h.	98-1 Self Certification of Product Chemistry Data with Attachments 
(This document is in PDF format and requires the Acrobat reader.) 

Other PR Notices can be found at     HYPERLINK
"http://www.epa.gov/opppmsd1/PR_Notices" 
http://www.epa.gov/opppmsd1/PR_Notices .

3.	Pesticide Product Registration Application Forms (These forms are in
PDF format and will require the Acrobat reader.)  

	

		a.	EPA Form No. 8570-1, Application for Pesticide
Registration/Amendment 

		b.	EPA Form No. 8570-4, Confidential Statement of Formula 

		c.	EPA Form No. 8570-27, Formulator’s Exemption Statement 

		d.	EPA Form No. 8570-34, Certification with Respect to Citations of
Data 

		e.	EPA Form No. 8570-35, Data Matrix 

4.	General Pesticide Information (Some of these forms are in PDF format
and will require the Acrobat reader.) 

		a.	Registration Division Personnel Contact List

b.	Biopesticides and Pollution Prevention Division (BPPD) Contacts

		c.	Antimicrobials Division Organizational Structure/Contact List 

d.	53 F.R.  15952, Pesticide Registration Procedures; Pesticide Data
Requirements (PDF format)

e.  	40 CFR Part 156, Labeling Requirements for Pesticides and Devices
(PDF format) 

		f.  	40 CFR Part 158, Data Requirements for Registration (PDF format) 

g.  	50 F.R.  48833, Disclosure of Reviews of Pesticide Data (November
27, 1985) 

Before submitting your application for registration, you may wish to
consult some additional sources of information.  These include: 

	1.	The Office of Pesticide Programs’ Web Site 

2.	The booklet “General Information on Applying for Registration of
Pesticides in the United States”, PB92-221811, available through the
National Technical Information Service (NTIS) at the following address: 

			National Technical Information Service (NTIS)

			5285 Port Royal Road

			Springfield, VA 22161 

The telephone number for NTIS is (703) 605-6000.  Please note that EPA
is currently in the process of updating this booklet to reflect the
changes in the registration program resulting from the passage of the
FQPA and the reorganization of the Office of Pesticide Programs.  We
anticipate that this publication will become available during the Fall
of 1998.  

3.	The National Pesticide Information Retrieval System (NPIRS) of Purdue
University’s Center for Environmental and Regulatory Information
Systems.  This service does charge a fee for subscriptions and custom
searches.  You can contact NPIRS by telephone at (765) 494-6614 or
through their Web site.  

4.	The National Pesticide Telecommunications Network (NPTN) can provide
information on active ingredients, uses, toxicology, and chemistry of
pesticides.  You can contact NPTN by telephone at (800) 858-7378 or
through their Web site:   HYPERLINK "http://npic.orst.edu" 
http://npic.orst.edu  .

The Agency will return a notice of receipt of an application for
registration or amended registration, experimental use permit, or
amendment to a petition if the applicant or petitioner encloses with his
submission a stamped, self-addressed postcard.  The postcard must
contain the following entries to be completed by OPP: 

			Date of receipt 

			EPA identifying number 

			Product Manager assignment 

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date of receipt and provide the EPA identifying File Symbol or petition
number for the new submission.  The identifying number should be used
whenever you contact the Agency concerning an application for
registration, experimental use permit, or tolerance petition.

To assist us in ensuring that all data you have submitted for the
chemical are properly coded and assigned to your company, please include
a list of all synonyms, common and trade names, company experimental
codes, and other names which identify the chemical (including
“blind” codes used when a sample was submitted for testing by
commercial or academic facilities).  Please provide a CAS number if one
has been assigned.

			

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 PAGE   57 

		Chlorine Dioxide RED	

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