[Federal Register Volume 89, Number 237 (Tuesday, December 10, 2024)]
[Proposed Rules]
[Pages 99184-99207]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-28332]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[EPA-HQ-OPP-2024-0431; FRL-12415-01-OCSPP]
Chlorpyrifos; Tolerance Revocation
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: EPA is proposing to revoke all tolerances for residues of
chlorpyrifos, except for those associated with the use of chlorpyrifos
on the following crops: alfalfa, apple, asparagus, tart cherry, citrus,
cotton, peach, soybean, strawberry, sugar beet, and spring and winter
wheat. This proposal also addresses the request to revoke all
chlorpyrifos tolerances contained in the September 12, 2007, petition
submitted by the Natural Resources Defense Council (NRDC) and Pesticide
Action Network North America (PANNA).
DATES: Comments must be received on or before February 10, 2025.
ADDRESSES: Submit your comments, identified by docket identification
(ID) number EPA-HQ-OPP-2024-0431, through the Federal eRulemaking
Portal at https://www.regulations.gov. Follow the online instructions
for submitting comments. Do not submit electronically any information
you consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Additional
instructions on commenting and visiting the docket, along with more
information about dockets generally, is available at https://www.epa.gov/dockets.
FOR FURTHER INFORMATION CONTACT: Patricia Biggio, Pesticide Re-
Evaluation Division (7508M), Office of Pesticide Programs,
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington,
DC 20460-0001; telephone number: 202-566-0700; email address:
[email protected].
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this action apply to me?
This action is directed to the public in general and may be of
interest to a wide range of stakeholders including environmental, human
health, and agricultural advocates; the chemical industry; pesticide
users; and members of the public interested in the sale, distribution,
or use of pesticides. Since others also may be interested, the Agency
has not attempted to describe all the specific entities that may be
affected by this action.
B. How can I get electronic access to other related information?
You may access a frequently updated electronic version of 40 CFR
part 180 through the Office of the Federal Register's e-CFR site at
https://www.ecfr.gov/current/title-40.
C. What action is the Agency proposing?
EPA is proposing to revoke all tolerances for residues of the
insecticide chlorpyrifos as contained in 40 CFR 180.342, except for
those tolerances associated with 11 uses that were proposed for
retention in the Agency's December 2020 Chlorpyrifos Proposed Interim
Decision (2020 PID). (Ref. 1) As a result of voluntary cancellations
and label amendments, registrations of chlorpyrifos will be limited in
terms of food uses to these crops within certain states, as proposed in
the 2020 PID and EPA's Updated Chlorpyrifos Refined Drinking Water
Assessment for Registration Review (September 2020) (``2020 DWA'') as
described in Unit III below. (Ref. 2)
Therefore, the Agency is proposing to revoke all other tolerances
that are not needed as a result of the cancellations, including uses in
food handling establishments and food service establishments. This
proposal will also address the request to revoke chlorpyrifos
tolerances in the pending 2007 Petition from NRDC and PANNA.
D. What is EPA's authority for taking this action?
Pursuant to its authority under section 408 of the Federal Food,
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a (https://www.govinfo.gov/link/uscode/21/346a), EPA may respond to a petition
filed with the Agency under FFDCA section 408(d) by issuing a proposed
and final rule under FFDCA section 408(e). The 2007 Petition requested
that EPA revoke chlorpyrifos tolerances, as well as cancel chlorpyrifos
registrations. EPA is proposing to revoke chlorpyrifos tolerances that
will no longer be necessary due to the cancellation of domestic uses on
those commodities. Under section 408(e) of the FFDCA, EPA may issue a
rule revoking tolerances after providing notice of a proposed
rulemaking and a period of not less than 60 days for public comment. 21
U.S.C. 346a(e).
E. What is the expected impact of this action?
The revocations of these tolerances are not expected to present
extraordinary circumstances because the registrants have requested,
pursuant to the Federal Insecticide, Fungicide, and Rodenticide Act
(FIFRA) section 6(f) (7 U.S.C. 136d(f)), to voluntarily cancel uses
associated with these tolerances. EPA is in the process of approving
those cancellation requests under FIFRA, which means that soon the
tolerances will no longer be needed to cover residues of chlorpyrifos
in or on those food commodities.
The revocations of tolerances could impact foreign producers who
use chlorpyrifos to control insect pests and importers of those
commodities. Shipments found to have residues could not be sold in the
United States, which may represent a loss to importers or their trading
partners. It is possible that these effects could have downstream
effects, such as raising costs to U.S. consumers of these commodities.
Regardless of the potential impacts of this action, tolerances can only
be maintained if they are safe, which is a risk-only analysis under the
FFDCA.
F. What can I do if I want the Agency to maintain, for import purposes,
a tolerance that the Agency proposes to revoke?
This proposed rule provides a 60-day public comment period. All
chlorpyrifos registrants have already voluntarily requested
cancellation of all the uses of chlorpyrifos associated with the
tolerances proposed for revocation in this notice. Once those
cancellations are effective, those uses of chlorpyrifos on these
commodities will no longer be registered in the United States, and once
use terminates under the applicable existing stocks provisions, the
tolerances will no longer be necessary to cover residues from use of
the pesticide. Any food being moved through interstate commerce after
tolerances are revoked would be covered by the FFDCA channels of trade
provision, 21 U.S.C. 346a(l)(5), as described in Unit VII.A. The
Agency's typical process, e.g., during registration review, is to
remove tolerances from the regulations that are no longer necessary.
This avoids confusion among the regulated community by reflecting
registered uses and label directions and helps with consistency in
enforcement under the FFDCA and FIFRA.
The only reason to retain a tolerance in such circumstances is for
import purposes. Any commenter seeking to retain tolerances for import
purposes
[[Page 99185]]
must provide a comment to that effect and include information
demonstrating the need for retaining a specific tolerance for specific
imports, even if they have previously provided this information; a
hypothetical need based on the potential for some commodities
containing chlorpyrifos residues to one day be imported into the United
States is insufficient.
If any data are necessary to retain the tolerances for import
purposes, EPA will issue an order in the Federal Register under FFDCA
section 408(f). The order would specify data needed and the timeframes
for submission of the data and would require that within 90 days some
person or persons notify EPA that they will submit the data. If the
data are not submitted as required in the order, EPA will take
appropriate action under FFDCA.
After considering comments that are received in response to this
proposed rule, EPA will issue a final rule.
G. What should I consider as I prepare my comments for EPA?
1. Submitting CBI. Do not submit CBI information to EPA through
https://www.regulations.gov or email. If you wish to include CBI in
your comment, please follow the applicable instructions at https://www.epa.gov/dockets/commenting-epa-dockets#rules and clearly mark the
part or all of the information that you claim to be CBI. In addition to
one complete version of the comment that includes information claimed
as CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for preparing your comments. When preparing and submitting
your comments, see the commenting tips at https://www.regulations.gov/faq.
3. Environmental justice. EPA seeks to achieve environmental
justice--the just treatment and meaningful involvement of all people,
regardless of income, race, color, national origin, Tribal affiliation,
or disability, in Agency decision-making and other Federal activities
that affect human health and the environment so that people are fully
protected from disproportionate and adverse human health and
environmental effects (including risks). To help address potential
environmental justice issues, the Agency seeks information on any
groups or segments of the population who, as a result of their
location, cultural practices, or other factors, may have atypical or
disproportionate and adverse human health impacts or environmental
effects from exposure to chlorpyrifos, compared to the general
population.
H. What is contained in this proposed rule?
The following provides a brief roadmap of the Units in this
proposed rule.
Unit II contains an overview of the relevant statutory
background under the FFDCA and FIFRA as well as the regulatory status
of chlorpyrifos. This Unit also provides a summary of the various
recent legal challenges to the chlorpyrifos tolerances.
Unit III describes the Agency's proposal to revoke
tolerances that will not be needed as a result of the approval of
registrants' requests to cancel chlorpyrifos uses on certain food
commodities.
Unit IV contains a safety determination that supports the
tolerances that are not proposed for revocation.
Unit V contains the Agency's responses to specific claims
raised in the 2007 Petition not otherwise addressed in the rest of the
proposed rule.
Units VI, VII, and VIII contain EPA's request for public
comment, discuss EPA's intention for phasing out the tolerances, and
consistency with other statutory requirements and executive orders.
II. Background
A. What is a tolerance?
A ``tolerance'' represents the maximum level for residues of
pesticide chemicals legally allowed in or on food, which includes raw
agricultural commodities, processed foods, and feed for animals. Under
the FFDCA, residues of a pesticide chemical that are not covered by a
tolerance or exemption from the requirement of a tolerance are
considered unsafe. See 21 U.S.C. 346a(a)(1). Foods containing unsafe
residues are deemed adulterated and may not be distributed in
interstate commerce. See 21 U.S.C. 331(a), 342(a)(2)(B). This applies
to both food treated domestically with a pesticide registered in the
United States or treated in another country and imported into the
United States. Thus, before registering any food-use pesticide (i.e., a
pesticide use that is likely to result in residues in or on food) under
FIFRA, 7 U.S.C. 136 et seq., EPA ensures that any necessary tolerances
or exemptions are in place. 40 CFR 152.112(g). EPA also establishes
tolerances or exemptions for pesticides not registered in the United
States in order for commodities treated with those pesticides to be
imported.
B. FFDCA/FIFRA Background
1. FFDCA
FFDCA section 408(b) authorizes EPA to establish a tolerance, if
the Agency determines that a tolerance is safe. See 21 U.S.C. 346a(b).
If EPA determines that a tolerance is not safe, EPA must modify or
revoke that tolerance. The FFDCA defines ``safe'' to mean 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 all other exposures for which there is reliable
information.'' 21 U.S.C. 346a(b)(2)(A)(ii). This includes exposure
through drinking water and in residential settings but does not include
occupational exposure.
FFDCA section 408(b)(2)(C) requires EPA to give special
consideration to the exposure of infants and children to the pesticide
chemical residue in establishing a tolerance and to ``ensure that there
is a reasonable certainty that no harm will result to infants and
children from aggregate exposure to the pesticide chemical
residue[s].'' 21 U.S.C. 346a(b)(2)(C). This provision also creates a
presumption that EPA will use an additional safety factor for the
protection of infants and children. Specifically, it directs that ``in
the case of threshold effects, . . . an additional tenfold margin of
safety for the pesticide chemical residue and other sources of exposure
shall be applied for infants and children to take into account
potential pre- and post-natal toxicity and completeness of the data
with respect to exposure and toxicity to infants and children.'' (21
U.S.C. 346a(b)(2)(C)) EPA is permitted to ``use a different margin of
safety for the pesticide chemical residue only if, on the basis of
reliable data, such margin will be safe for infants and children.''
(Id.) Due to Congress's focus on both prenatal and post-natal toxicity,
EPA has interpreted this additional safety factor as pertaining to
risks to infants and children that arise due to prenatal exposure as
well as to exposure during childhood years. This section providing for
the special consideration of infants and children in section
408(b)(2)(C) was added to the FFDCA by the Food Quality Protection Act
(FQPA) in 1996; therefore, this additional margin of safety is referred
to throughout this proposed rule as the FQPA safety factor (SF).
Finally, FFDCA section 408(b)(2)(D) contains several factors that
EPA considers when making determinations about establishing, modifying,
or
[[Page 99186]]
revoking tolerances. 21 U.S.C. 346a(b)(2)(D).
Any person may file a petition requesting that EPA establish,
modify, or revoke a tolerance. 21 U.S.C. 346a(d)(1). After publishing
notice of receipt of that petition and after giving due consideration,
EPA may issue a final or proposed rule establishing, modifying, or
revoking the tolerances or issue an order denying the petition. 21
U.S.C. 346a(d)(4)(A).
2. FIFRA
Under FIFRA (7 U.S.C. 136 et seq.), EPA regulates the sale,
distribution, and use of pesticides. While FFDCA authorizes the
establishment of legal limits for pesticide residues in food, FIFRA
generally requires the approval of pesticides prior to their sale and
distribution (id. at section 136a(a)) and establishes a registration
regime for regulating the use of pesticides. In order for a pesticide
to be registered, EPA must determine that a pesticide ``will not
generally cause unreasonable adverse effects on the environment,''
among other things. (Id. at section 136a(c)(5)) The term ``unreasonable
adverse effects on the environment'' is defined to include ``a human
dietary risk from residues that results from a use of a pesticide in or
on any food inconsistent with the standard under section 346a of Title
21.'' (Id. at section 136(bb)) The FFDCA safety standard was integrated
into the FIFRA registration standard through the FQPA, which also
directed that EPA coordinate, to the extent practicable, revocations of
tolerances with pesticide cancellations under FIFRA. (21 U.S.C.
346a(l)(1)).
Also under FIFRA, EPA is required to re-evaluate existing
registered pesticides every 15 years in a process called ``registration
review.'' (7 U.S.C. 136(a)(g)) The purpose of registration review is
``to ensure that each pesticide registration continues to satisfy the
FIFRA standard for registration,'' (40 CFR 155.40(a)(1)) taking into
account changes that have occurred since the last registration
decision, including any new relevant scientific information and any
changes in the law or regulations, policy, risk-assessment procedures
or methods, and data requirements. (40 CFR 155.53(a)) To ensure that a
pesticide continues to meet the standard for registration, EPA must
determine, based on the available data, including any additional
information that has become available since the pesticide was
originally registered or previously re-evaluated, that the pesticide
does not cause ``unreasonable adverse effects on the environment.'' (7
U.S.C. 136a(c)(1), (5); see also 40 CFR 152.50) As part of the
registration review of a pesticide, EPA also evaluates whether existing
tolerances are safe and whether any changes to existing tolerances are
necessary or appropriate. Pesticide products that do not meet the FIFRA
standard for registration may be cancelled pursuant to the procedures
in FIFRA section 6, 7 U.S.C. 136d. That provision of FIFRA also
provides a mechanism for registrants to request voluntary cancellation
of registered products or to request termination of specific uses on
any registered product, at any time for any reason. 7 U.S.C. 136d(f).
If a registrant requests such cancellation or use termination, EPA
publishes notice of that request and allows for a public comment
period. 7 U.S.C. 136d(f)(1)(B) and (C). After the public comment
period, EPA may approve or deny the request. 7 U.S.C. 136d(f)(1)(D).
C. Chlorpyrifos Background
Chlorpyrifos (0,0-diethyl-0-3,5,6-trichloro-2-pyridyl
phosphorothioate) is a broad-spectrum, chlorinated organophosphate (OP)
insecticide. Chlorpyrifos also forms the more toxic and potent
acetylcholinesterase (AChE) inhibitor, chlorpyrifos oxon.
Chlorpyrifos has been registered for use in the United States since
1965. These uses have included a wide range of food crops (e.g.,
soybean, wheat) and non-food use sites (e.g., tobacco, ornamental
flowering plants, turf), as well as public health uses (e.g., aerial
and ground-based fogger mosquito adulticide treatments) and residential
uses (e.g., roach bait products, and individual fire ant mound
treatments). In 2000, chlorpyrifos registrants reached an agreement
with EPA to voluntarily cancel all residential use products except
those registered for ant and roach baits in child-resistant packaging
and fire ant mound treatments. Most recently, as discussed later in
this document, chlorpyrifos registrants have voluntarily requested to
cancel all food uses except the 11 uses described in Unit III. Pursuant
to those requests, EPA has already cancelled most of those registered
food uses and expects to process the remaining cancellation requests by
the end of this calendar year (2024). (Ref. 3-8).
EPA is currently working to complete the registration review of
chlorpyrifos. As part of that process, EPA has completed multiple human
health risk assessments (HHRAs) since 2011. As additional data became
available for chlorpyrifos and its metabolite of concern, chlorpyrifos
oxon, EPA completed revised draft human health risk assessments in
2014, 2016, and 2020. A refined drinking water assessment (DWA) was
completed in 2016 (2016 DWA), and the Updated DWA was completed in 2020
(2020 DWA). In December 2020, EPA issued the Chlorpyrifos Proposed
Interim Decision (2020 PID). (Ref. 1) At this time, EPA is working on
responding to comments received on the 2020 PID and supporting risk
assessments and on preparing an updated human health risk assessment
and amended proposed interim registration review decision. EPA
anticipates issuing an amended PID in 2026 followed by the Chlorpyrifos
Interim Decision.
It should be noted that there has been an international effort to
develop a battery of new approach methodologies (NAMs) to inform the
developmental neurotoxicity (DNT) potential for individual chemicals.
The assays in this battery are expected to provide a mechanistic
understanding of the underlying biological processes that may be
vulnerable to chemically-induced disruption. Since the integration of
data from the DNT NAM battery for the chlorpyrifos risk assessment is
in progress, it has not been incorporated into the risk assessment that
supports this rulemaking. It is intended to be incorporated into the
amended human health risk assessment anticipated for release in 2025 in
support of registration review, and the Agency will provide any updates
on the status of this effort through the ongoing registration review of
chlorpyrifos.
D. 2007 Petition and Associated Litigation
In September 2007, PANNA and the NRDC jointly submitted to EPA a
petition under FFDCA section 408(d), seeking revocation of all
chlorpyrifos tolerances. The 2007 Petition also sought the cancellation
of all chlorpyrifos pesticide product registrations under FIFRA section
6, 7 U.S.C. 136d. The 2007 Petition raised several claims, which are
discussed in Unit V., regarding both EPA's 2006 FIFRA reregistration
eligibility decision (RED) and active registrations of chlorpyrifos in
support of the request for tolerance revocations and product
cancellations.
In March 2009, EPA decided it would be appropriate to address these
issues and the 2007 Petition claims in connection with the registration
review of chlorpyrifos under FIFRA section 3(g) and decided to expedite
that review, intending to finalize it several years in advance of the
registration review deadline at that time, October 1, 2022.
[[Page 99187]]
On July 16, 2012, EPA denied the one FIFRA claim in a letter to the
Petitioners and offered a partial response on several of the FFDCA
claims; however, because the complexity of these scientific issues
precluded EPA from finishing its review according to EPA's original
timeline, the Petitioners brought legal action in the U.S. Court of
Appeals for the Ninth Circuit to compel EPA to either issue an order
denying the 2007 Petition or to grant the 2007 Petition by initiating
the tolerance revocation process. On August 10, 2015, the Ninth Circuit
ordered EPA to ``issue either a proposed or final revocation rule or a
full and final response to the administrative [P]etition by October 31,
2015.'' In re Pesticide Action Network N. Am., 798 F.3d 809, 815 (9th
Cir. 2015).
In response to that 2015 order, EPA issued a proposed rule to
revoke all tolerances for chlorpyrifos on October 28, 2015 (published
in the Federal Register on November 6, 2015 (80 FR 69080)). Although
EPA noted that further evaluation might enable more tailored risk
mitigation, EPA was unable to conclude, based on the information before
EPA at the time, that the tolerances were safe, since the aggregate
exposure to chlorpyrifos, driven by drinking water exposures, exceeded
safe levels. In November 2016, EPA issued a notice of data availability
announcing the availability of a revised human health risk assessment.
(81 FR 81049) (Nov. 17, 2016) (Ref. 9)
In the meantime, the Ninth Circuit ordered EPA to take final action
on its proposed revocation rule and issue its final response to the
Petition by December 30, 2016. In re Pesticide Action Network N. Am.,
808 F.3d 402 (9th Cir. 2015). EPA requested an extension of the
deadline in order to be able to fully consider the July 2016 FIFRA
Scientific Advisory Panel (SAP) report regarding chlorpyrifos
toxicology, but the Ninth Circuit ordered EPA to complete its final
action by March 31, 2017. In re Pesticide Action Network of North
America v. EPA, 840 F.3d 1014 (9th Cir. 2016).
Accordingly, EPA issued a formal denial of the FFDCA claims in the
2007 Petition in an order issued in March 2017. (Ref. 10) In that 2017
Petition Denial, EPA concluded that it was not required to complete--
and would not complete--any tolerance revocation of chlorpyrifos
without resolution of those issues during the ongoing FIFRA
registration review of chlorpyrifos. Chlorpyrifos; Order Denying PANNA
and NRDC's Petition to Revoke Tolerances, 82 FR 16581 (April 5, 2017)
(``2017 Petition Denial''). EPA also denied objections filed in
response to the 2017 Petition Denial on July 24, 2019. See
Chlorpyrifos; Final Order Denying Objections to March 2017 Petition
Denial Order, 84 FR 35555 (July 24, 2019) (``2019 Objections Denial'').
In the 2019 Objections Denial, EPA concluded that it was appropriate to
deny the objections related to new issues raised after EPA's 2006
tolerance reassessment and reregistration of chlorpyrifos as these
issues are being addressed according to the schedule for EPA's ongoing
registration review of chlorpyrifos.
The 2019 Objections Denial was challenged by several farmworker
advocacy groups and States, and in April 2021, the Ninth Circuit issued
its decision, finding that EPA's denial was arbitrary and capricious
based on the record before the court. See League of United Latin Am.
Citizens, et al., v. Regan, 996 F.3d 673 (9th Cir. 2021). The Ninth
Circuit vacated EPA's petition response and ordered EPA to grant the
2007 Petition; to issue a final rule either revoking all chlorpyrifos
tolerances or modifying the chlorpyrifos tolerances, provided EPA could
make a determination that those modified tolerances met the safety
standard mandated by the FFDCA; and to cancel registered chlorpyrifos
products or uses associated with the revoked tolerances. The Ninth
Circuit ordered EPA to issue that final rule within 60 days of the
issuance of the mandate and to cancel the registered pesticides in a
timely manner. Frustrated with the ``[then-] thirteen years of
interminable delay,'' the Ninth Circuit concluded that ``further
factfinding'' would not be reasonable and that ``immediate issuance of
a final regulation is the only reasonable action,'' citing the FFDCA
provision authorizing issuance of a final rule `` `without further
notice and without further period for public comment.' '' See id. at
702, citing 21 U.S.C. 136a(d)(4)(A)(i) (emphasis in original).
On August 30, 2021, EPA complied with the Ninth Circuit's ruling by
granting the 2007 Petition and issuing the Final Tolerance Rule for
Chlorpyrifos, which revoked all tolerances for chlorpyrifos. See 86 FR
48315 (Aug. 30, 2021) (``2021 Final Rule''). EPA explained in the 2021
Final Rule that it was unable to determine that there was a reasonable
certainty of no harm for aggregate exposure, including food, drinking
water, and residential exposure, based on the available data and the
anticipated exposures from all of the then-currently registered uses of
chlorpyrifos. EPA's analysis indicated that risk from aggregate
exposures from all of the then-registered uses would exceed the
Agency's levels of concern. To satisfy international trade
considerations, the 2021 Final Rule allowed the tolerances to remain in
effect for six months until February 28, 2022, at which time the
tolerances expired. Pursuant to FFDCA section 408(g), registrants and
grower groups, among others, filed objections to the 2021 Final Rule,
which EPA denied on February 28, 2022. See Chlorpyrifos; Final Order
Denying Objections, Requests for Hearings, and Requests for a Stay of
the August 2021 Tolerance Final Rule. 87 FR 11222 (Feb. 28, 2022)
(``2022 Objections Denial'').
The 2021 Final Rule and 2022 Objections Denial were challenged by a
chlorpyrifos registrant, Gharda Chemicals International, Inc. (Gharda),
and 19 grower groups in the U.S. Court of Appeals for the Eighth
Circuit. The grower groups included Red River Valley Sugarbeet Growers
Association, U.S. Beet Sugar Association, American Sugarbeet Growers
Associations, Southern Minnesota Better Sugar Cooperative, American
Crystal Sugar Company, Minn-Dak Farmer Cooperative, American Farm
Bureau Federation, American Soybean Association, Iowa Soybean
Association, Minnesota Soybean Growers Association, Missouri Soybean
Association, Nebraska Soybean Association, South Dakota Soybean
Association, North Dakota Soybean Growers Association, National
Association of Wheat Growers, Cherry Marketing Institute, Florida Fruit
and Vegetable Association, Georgia Fruit and Vegetable Growers
Association, and the National Cotton Council of America. These
petitioners argued, among other things, that EPA should have modified
tolerances by leaving tolerances in place consistent with the 11 uses
proposed the 2020 PID, rather than revoking all tolerances.
On November 2, 2023, the Eighth Circuit issued its decision,
vacating the 2021 Final Rule (and EPA's response to the 2007 Petition
once again) and remanding the matter to EPA for further proceedings.
See Red River Valley Sugarbeet Growers Ass'n, et al. v. Regan, 85 F.4th
881 (8th Cir. 2023). The Eighth Circuit's decision noted that the
Agency had ``identified 11 specific candidates'' of food and feed crop
uses in the 2020 PID as part of Registration Review. Although the 2021
Final Rule (and the 2022 Objections Denial) explained why EPA was not
modifying the tolerances consistent with the 2020 PID, the Eighth
Circuit concluded that the 2021 Final Rule ignored modification of
tolerances as an option for addressing the Ninth Circuit's
[[Page 99188]]
mandate and thus was arbitrary and capricious. The Eighth Circuit's
mandate issued on December 28, 2023, at which time all chlorpyrifos
tolerances were automatically reinstated. EPA amended the Code of
Federal Regulations on February 5, 2024, to reflect the Eighth
Circuit's reinstatement of chlorpyrifos tolerances. See Chlorpyrifos;
Reinstatement of Tolerances, 89 FR 7625 (Feb. 5, 2024).
III. Proposed Rule
In this document, EPA is proposing to revoke tolerances to reflect
registrants' requests to voluntarily cancel food uses and submission of
label amendments consistent with the 2020 PID and supporting documents.
EPA anticipates approving all submitted cancellation requests by the
end of 2024. After approval of the cancellation requests and label
amendments, the only food uses that will remain on federally registered
chlorpyrifos products are listed below and will be limited to the
following States:
1. Alfalfa: Arizona, Colorado, Iowa, Idaho, Illinois, Kansas,
Michigan, Minnesota, Missouri, Montana, North Dakota, Nebraska, New
Mexico, Nevada, Oklahoma, Oregon, South Dakota, Texas, Utah,
Washington, Wisconsin, and Wyoming.
2. Apple: Alabama, Delaware, Georgia, Idaho, Indiana, Kentucky,
Maryland, Michigan, New Jersey, New York, Ohio, Oregon, Pennsylvania,
Tennessee, Virginia, Vermont, Washington, West Virginia, and
Washington, DC.
3. Asparagus: Michigan.
4. Tart cherry: Michigan.
5. Citrus: Alabama, Florida, Georgia, North Carolina, South
Carolina, and Texas.
6. Cotton: Alabama, Florida, Georgia, North Carolina, South
Carolina, and Virginia.
7. Peach: Alabama, Delaware, Florida, Georgia, Maryland, Michigan,
North Carolina, New Jersey, New York, Ohio, Pennsylvania, South
Carolina, Texas, Virginia, Vermont, West Virginia, and Washington, DC.
8. Soybean: Alabama, Colorado, Florida, Georgia, Iowa, Illinois,
Indiana, Kansas, Kentucky, Minnesota, Missouri, Montana, North
Carolina, North Dakota, Nebraska, New Mexico, Ohio, Oklahoma,
Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia,
Wisconsin, West Virginia, and Wyoming.
9. Strawberry: Oregon
10. Sugar beet: Iowa, Idaho, Illinois, Michigan, Minnesota, North
Dakota, Oregon, Washington, Wisconsin.
11. Wheat:
a. Spring wheat: Colorado, Kansas, Missouri, Montana, North Dakota,
Nebraska, South Dakota, and Wyoming.
b. Winter wheat: Colorado, Iowa, Kansas, Minnesota, Missouri,
Montana, North Dakota, Nebraska, Oklahoma, South Dakota, Texas, and
Wyoming.
EPA notes that not all chlorpyrifos products are registered for
these uses in all of the above listed States. If the use is not
registered on a particular chlorpyrifos product, it must be added via
the FIFRA section 3 registration process in order for that product to
be used in a particular State. Moreover, EPA notes that since the
issuance of the 2020 PID, several States have prohibited use of
chlorpyrifos, including California, Hawaii, New York, Maryland, and
Oregon. States may regulate the sale or use of federally registered
pesticides within their State. Although these particular States have
adopted additional restrictions, the voluntary cancellation requests
for the federally registered uses only reflected EPA's proposal in the
2020 PID and did not incorporate any additional restrictions at the
State level. As a result, EPA's proposed tolerance revocations reflect
only the adjustments to the federal registrations, but the continued
registration review of chlorpyrifos allows for further consideration of
this issue.
In addition, the submitted label amendments are consistent with the
reduced application frequency and rates for these uses that were used
in the 2020 DWA and support the Estimated Drinking Water Concentration
(EDWC) calculations. (Ref. 2) EPA expects to approve the last of these
label amendments by the end of 2024. Consistent with the terms of the
cancellation orders, use of these previously registered chlorpyrifos
products on any crops beyond the 11 uses listed above and restricted as
described herein will be prohibited after June 30, 2025.
To cover residues of chlorpyrifos in food from these remaining food
uses, the following existing tolerances are not being revoked: alfalfa,
forage; alfalfa, hay; apple, apple, wet pomace; beet, sugar, dried
pulp; beet, sugar, molasses; beet, sugar, roots; beet, sugar, tops;
cattle, fat; cattle, meat; cattle, meat byproducts; cherry, tart;
citrus, dried pulp; citrus, oil; cotton, undelinted cotton seed; egg;
fruit, citrus, group 10; goat, fat; goat, meat; goat, meat byproducts;
hog, fat; hog, meat; hog, meat byproducts; horse, meat; horse, meat
byproducts; milk, fat (reflecting 0.01 ppm in whole milk); peach;
poultry, fat; poultry, meat; poultry, meat byproducts; sheep, fat;
sheep, meat; sheep, meat byproducts; soybean, seed; strawberry; wheat,
forage; wheat, grain; and wheat, straw in section 40 CFR 180.342(a) and
asparagus in 180.342(c).
EPA is proposing to revoke all other tolerances for residues of
chlorpyrifos on specific food commodities (40 CFR 180.342(a)(1)); on
all food commodities treated in food handling and food service
establishments in accordance with prescribed conditions (40 CFR
180.342(a)(2) and(a)(3)); and on grape when used under regional
registrations (40 CFR 180.342(c)).
EPA is proposing these tolerance revocations because all the
registrants have submitted voluntary cancellation requests for all food
uses that trigger the need for those tolerances. Moreover, all
registrants retaining any of the 11 food uses listed above have
submitted label amendments that limit uses to the specific States
listed above and restrict application rates and application frequency
consistent with the assumptions supporting the 2020 DWA. As of the
publication of this proposed rule, 41 products have been cancelled, and
12 products have had all food uses but the 11 uses identified above
cancelled. EPA has approved amended labels for 15 products. EPA is
currently working to process and expects to complete its issuance of
cancellation orders by the end of 2024, at which time no food uses
beyond the 11 identified above will remain registered.
Because of the cancellation of these uses, these tolerances will no
longer be needed to cover residues from use of the pesticide within the
United States. Removing unnecessary tolerances helps to avoid confusion
among stakeholders about where the pesticide can be used and improves
coordination under FIFRA and the FFDCA. EPA's typical practice when
tolerances are no longer needed due to the cancellation of registered
uses or products is to remove them from the Code of Federal
Regulations, usually carried out after being discovered as not
necessary in registration review. See, e.g., Pesticide Tolerance;
Exemptions, Petitions, Revocations, etc.: Implementing Registration
Review Decisions for Certain Pesticides; Aluminum tris (O-
ethylphosphonate), Carbon disulfide, et al., (88 FR 46077) (July 19,
2023). (Ref. 11) There is no requirement, however, to wait until the
conclusion of registration review, and since EPA is aware of the lack
of necessity of these tolerances now, EPA's current proposed rule
facilitates a more-timely reflection of the actual use status within
the tolerance regulation to provide greater clarity to stakeholders,
including growers and States, to avoid confusion
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about what is allowed under the FFDCA and FIFRA. Moreover, although the
EPA's conclusions and rationale for the revocation of these tolerances
differ from the claims outlined in the Petitioner's 2007 request to
revoke all tolerances, the EPA is, in part, taking the action requested
by the 2007 Petition.
In some cases, the registrants' requests to terminate these food
uses or cancel registered chlorpyrifos products included requests to
continue sale, distribution, and use of existing stocks for a certain
period of time after cancellation. Existing stocks are those stocks of
registered pesticide products that were in the United States and that
were packaged, labeled, and released for shipment prior to the
effective date of the cancellation action. Under those applicable
cancellation orders, some existing stocks of previously registered
chlorpyrifos products may be used on food until June 30, 2025.
Therefore, EPA is proposing that the final rule revoking the
unnecessary tolerances set an expiration date for those tolerances
being revoked of July 1, 2025. This approach would align the
permissible use period allowed under the cancellation orders with the
coverage of the existing tolerance to allow for clearer coverage under
section 408(l)(5) of the FFDCA. Under that provision, residues of a
pesticide chemical in or on food will not render that food adulterated
despite the revocation of a tolerance as long as the residue is present
as a result of a lawful application of the pesticide and does not
exceed the tolerance level that was authorized at the time of the
application. See 21 U.S.C. 346a(l)(5). In addition, this approach would
provide for a reasonable interval for exporting countries to adjust to
the new tolerance restrictions consistent with the United States'
obligations under the World Trade Organization Agreement on the
Application of Sanitary and Phytosanitary Measures (SPS Agreement).
IV. Safety of the Remaining Tolerances
As noted in the previous Unit, in a typical revocation action
following the cancellation of registered products or uses, EPA would
propose to remove tolerances that are no longer necessary. Those
actions typically do not require a rationale for justifying retention
of the tolerances that are not affected by that action, as revocation
does not impact the prior safety determinations made for the tolerances
left in place.
Chlorpyrifos, however, presents an unusual situation due to the
litigation history and the pending 2007 Petition. The last formal
determination that EPA made concerning chlorpyrifos tolerances was in
the 2021 Final Rule, in which EPA concluded that aggregate exposure to
chlorpyrifos, based on all registered food uses on chlorpyrifos
products at that time, was unsafe. That rule was issued in response to
a Ninth Circuit order, which vacated EPA's 2017 Petition Denial and
2019 Objections Denial in full and ordered EPA to issue a final rule
revoking all tolerances or modifying tolerances, as long as a safety
determination supported those modified tolerances. Then the Eighth
Circuit reinstated those tolerances through vacatur of the 2021 Final
Rule, despite EPA's finding that those tolerances were unsafe based on
uses that were registered at that time and noted that EPA should have
considered the option of retaining tolerances for the 11 uses proposed
in the 2020 PID in its 2021 Final Rule. In addition, the 2007 Petition
asserted that all chlorpyrifos tolerances were unsafe and should be
revoked. Because EPA's proposed rule does not revoke all chlorpyrifos
tolerances, EPA is providing an updated determination of safety
supporting the tolerances that are not being revoked. This approach and
the related FIFRA cancellation actions satisfy the Eighth Circuit's
remand for further proceedings and the Ninth Circuit's directive to
ensure that any modified tolerances are safe, without further
factfinding and delay.
As indicated in Unit III., all chlorpyrifos registrants have
submitted requests to voluntarily cancel all but 11 food uses of
chlorpyrifos and to amend labels that limit those food uses in several
ways, i.e., limiting uses to specific States and restricting
application rates and application frequency. After cancellation of all
uses but the 11 food uses listed in Unit III, amendment of those uses
on labels as described, and the termination of existing stocks terms,
which EPA expects no later than June 30, 2025, EPA anticipates that
exposure to chlorpyrifos in food and drinking water will align with the
calculations in the 2020 DWA, the 2020 human health risk assessment,
and the proposed determinations in the 2020 PID. The cancellations and
label amendments are reducing the amount of chlorpyrifos being used--
and thus being applied to food and getting into drinking water.
The safety determination in this document is based on the
anticipated aggregate exposures expected as a result of the
cancellation of most of the registered food uses and, on the analysis
conducted in the 2020 HH DRA and the 2020 DWA. As noted above, the
registration review process is ongoing, and there is a possibility that
additional information may alter the Agency's conclusions once that
process has been completed. However, for purposes of this rule and in
an effort not to further delay progress on this rulemaking or in
responding to the FFDCA petition, EPA is relying on the currently
available scientific documents to conclude that the tolerances not
being revoked are safe, i.e., that there is a reasonable certainty that
no harm will result from the aggregate exposure to chlorpyrifos. As
noted in this Unit, the aggregate exposures assessed reflect the
anticipated exposures to chlorpyrifos residues in drinking water after
the cancellation of most food uses of chlorpyrifos, rather than
chlorpyrifos residues in drinking water based on the wider set of
previously registered food uses as was done in the 2021 Final Rule.
EPA's full risk conclusions supporting this proposed response are
set forth in Chlorpyrifos: Third Revised Human Health Risk Assessment
for Registration Review (September 2020) (``2020 HH DRA'') and the 2020
DWA. (Ref. 12 and 2) EPA's assessment supports a conclusion that
aggregate exposures (including residential exposures and food and
drinking water exposures anticipated from the remaining registered
chlorpyrifos uses after the cancellation orders are issued and amended
labels are approved under FIFRA) are safe.
A. EPA's Hazard Assessment for Chlorpyrifos
1. General Approach to Hazard Identification, Dose-Response Assessment,
and Extrapolation
Any risk assessment begins with an evaluation of a chemical's
inherent properties, and whether those properties have the potential to
cause adverse effects (i.e., a hazard identification). In evaluating
toxicity or hazard, EPA reviews toxicity data, typically from studies
with laboratory animals, to identify any adverse effects on the test
subjects. Where available and appropriate, EPA will also take into
account studies involving humans, including human epidemiological
studies. The animal toxicity database for a conventional, food use
pesticide usually consists of studies investigating a broad range of
endpoints including potential for carcinogenicity, mutagenicity,
developmental and reproductive toxicity, and neurotoxicity. These
studies include gross and microscopic effects on organs and tissues,
functional effects on bodily organs and systems, effects on blood
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parameters (such as red blood cell (RBC) count, hemoglobin
concentration, hematocrit, and a measure of clotting potential),
effects on the concentrations of normal blood chemicals (including
glucose, total cholesterol, urea nitrogen, creatinine, total protein,
total bilirubin, albumin, hormones, and enzymes such as alkaline
phosphatase, alanine aminotransferase and cholinesterase), and
behavioral or other gross effects identified through clinical
observation and measurement. EPA examines whether adverse effects are
caused by different durations of exposure ranging from short-term
(acute) to long-term (chronic) pesticide exposure and different routes
of exposure (oral, dermal, inhalation). Further, EPA evaluates
potential adverse effects in different age groups (adults as well as
fetuses and juveniles). (Ref. 13 at 8-10).
Once a pesticide's potential hazards are identified, EPA determines
a toxicological level of concern for evaluating the risk posed by human
exposure to the pesticide. In this step of the risk assessment process,
EPA essentially evaluates the levels of exposure to the pesticide at
which effects might occur. An important aspect of this determination is
assessing the relationship between exposure (dose) and response (often
referred to as the dose-response analysis). In evaluating a chemical's
dietary risks, EPA uses a reference dose (RfD) approach, which
typically involves a number of considerations including:
A ``point of departure'' (PoD): Typically, the PoD is the
value from a dose-response curve that is at the low end of the
observable data in laboratory animals and that is the toxic dose that
serves as the ``starting point'' in extrapolating a risk to the human
population, although a PoD can also be derived from human data as well.
PoDs are selected to be protective of the most sensitive adverse toxic
effect for each exposure scenario and are chosen from toxicity studies
that show clearly defined No Observed Adverse Effect Levels (NOAELs) or
Lowest Observed Adverse Effect Levels (LOAELs), dose-response
relationships, and relationships between the chemical exposure and
effect. EPA will select separate PoDs, as needed, for each expected
exposure duration (e.g., acute, chronic, short-term, intermediate-term)
and route of exposure (e.g., oral, dermal, inhalation). For
chlorpyrifos, as discussed later in this Unit, EPA derived PoDs based
on 10% RBC AChE inhibition in the 2020 HH DRA.
Interspecies extrapolation: Because most PoDs are derived
from toxicology studies in laboratory animals, there is a need to
extrapolate from animals to humans. In typical risk assessments, a
default tenfold (10X) uncertainty factor is used to address the
potential for a difference in toxic response between humans and animals
used in toxicity tests. For chlorpyrifos, as described further below,
EPA used a sophisticated model called a physiologically based
pharmacokinetic-pharmacodynamic (PBPK-PD) model that accounts for
differences in laboratory animals and humans, thereby obviating the
need for the default interspecies factor.
Intraspecies extrapolation: To address the potential for
differences in sensitivity in the toxic response across the human
population, EPA conducts intraspecies extrapolation. In typical risk
assessments, a 10X default uncertainty factor is used. For
chlorpyrifos, the PBPK-PD model used to derive PoDs also accounts for
differences in metabolism and toxicity response across the human
population for some age groups and some subpopulations, which allows
the default factor of 10X to be refined in accordance with EPA's 2014
Guidance for Applying Quantitative Data to Develop Data-Derived
Extrapolation Factors for Interspecies and Intraspecies Extrapolation.
Food Quality Protection Act safety factor (FQPA SF): The
FFDCA section 408(b)(2)(C) instructs EPA, in making its ``reasonable
certainty of no harm'' finding, that in ``the case of threshold
effects, an additional tenfold margin of safety for the pesticide
chemical residue and other sources of exposure shall be applied for
infants and children to take into account potential pre- and post-natal
toxicity and completeness of data with respect to exposure and toxicity
to infants and children.'' Section 408(b)(2)(C) further states that
``the Administrator may use a different margin of safety for the
pesticide chemical residue only if, on the basis of reliable data, such
margin will be safe for infants and children.'' For chlorpyrifos, EPA
is retaining the default 10X FQPA SF as discussed later in this Unit.
In the human health risk assessment process, as indicated above,
EPA uses the selected PoD to calculate a RfD for extrapolating risk.
The RfD is calculated by dividing the selected PoD by any applicable
interspecies and intraspecies factors and other relevant uncertainty
factors such as LOAEL to NOAEL factor or database uncertainty factor.
After calculating the RfD, as indicated above, EPA retains an
additional safety factor of 10X to protect infants and children (the
FQPA SF), unless reliable data support selection of a different factor,
as required under the FFDCA. As described in EPA's policy for
determining the appropriate FQPA SF, this additional safety factor
often overlaps with other traditional uncertainty factors (e.g., LOAEL
to NOAEL factor or database uncertainty factor), but it might also
account for residual concerns related to pre- and post-natal toxicity
or exposure. (Ref. 14 at 13-16) In implementing FFDCA section 408, EPA
calculates a variant of the RfD referred to as a Population Adjusted
Dose (PAD), by dividing the RfD by the FQPA SF. Risk estimates less
than 100% of the PAD are safe.
2. Toxicological Effects of Chlorpyrifos
Consistent with FFDCA section 408(b)(2)(D), EPA has reviewed the
available scientific data and other relevant information for
chlorpyrifos in support of this action. For over two decades, EPA has
evaluated the scientific evidence surrounding the different health
effects associated with chlorpyrifos. The Agency has conducted
extensive reviews of the scientific literature on health outcomes
associated with chlorpyrifos and presented approaches for evaluating
and using that information to the FIFRA Scientific Advisory Panel
(SAP), on several occasions, as discussed in Unit V of the 2021 Final
Rule. See 86 FR at 48320-21. (Note: The FIFRA SAP is a federal advisory
committee created by FIFRA section 25(d), 7 U.S.C. 136w(d), and serves
as EPA's primary source of external, independent, scientific peer
review for significant regulatory and policy matters involving
pesticides).
Chlorpyrifos has been tested in toxicological studies for the
potential to cause numerous different adverse outcomes (e.g.,
reproductive toxicity, developmental toxicity, cancer, genotoxicity,
dermal toxicity, endocrine toxicity, inhalation toxicity, and
immunotoxicity). Chlorpyrifos has an established neurotoxic mode of
action, and neurotoxicity is the most sensitive effect in all species,
routes, and lifestages. The hazard characterization for chlorpyrifos
and its oxon is based on adverse health effects in animals and humans
related to two different neurotoxic endpoints: AChE inhibition and
potential for neurodevelopmental effects. AChE inhibition is being used
to derive the PODs for risk assessment. These PODs are protective for
neurotoxic effects related to AChE inhibition and potential downstream
neurotoxic effects. A weight-of-the-evidence (WOE) analysis on the
potential for neurodevelopmental effects following chlorpyrifos
exposure considered (1) whether chlorpyrifos
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causes long-term effects from prenatal and/or early lifestage exposure
and (2) whether adverse effects can be attributed to doses lower than
those which elicit 10% inhibition of RBC AChE. (Ref. 12 at 6) The FIFRA
SAP reports have rendered numerous recommendations for additional study
and sometimes conflicting advice for how EPA should consider (or not
consider) the available data in conducting EPA's registration review
human health risk assessment for chlorpyrifos.
The remainder of this Unit IV.A.2. discusses the Agency's
assessment of the science relating to AChE inhibition and the potential
for neurodevelopmental effects. Other adverse outcomes besides AChE
inhibition and neurodevelopment are less sensitive and are thus not
discussed in detail here. Further information concerning those effects
can be found in the 2000 human health risk assessment which supported
the RED and the 2011 preliminary human health risk assessment. (Ref. 15
and 16).
a. Acetylcholinesterase (AChE) Inhibition
Chlorpyrifos, like other organophosphate pesticides, affects the
nervous system by inhibiting AChE, an enzyme necessary for the proper
functioning of the nervous system and ultimately leading to signs of
neurotoxicity. This mode of action, in which AChE inhibition leads to
neurotoxicity, is well-established, and thus has been used as basis for
the PoD for organophosphate human health risk assessments, including
chlorpyrifos. This science policy is based on decades of work, which
shows that AChE inhibition is the initial event in the pathway to
cholinergic neurotoxicity.
The Agency has conducted a comprehensive review of the available
data and public literature regarding this adverse effect from
chlorpyrifos. (Ref. 17 at 24-25, Ref. 16 at 25-27) There are many
chlorpyrifos studies evaluating RBC AChE inhibition or the brain in
multiple lifestages (gestational, fetal, post-natal, and non-pregnant
adult), multiple species (rat, mouse, rabbit, dog, human), methods of
oral administration (oral gavage with corn oil, dietary, gavage via
milk) and routes of exposure (oral, dermal, inhalation via vapor and
via aerosol). In addition, chlorpyrifos is unique in the availability
of AChE data from peripheral tissues in some studies (e.g., heart,
lung, liver). There are also literature studies comparing the in vitro
AChE response to a variety of tissues which show similar sensitivity
and intrinsic activity. Across the database, brain AChE tends to be
less sensitive than RBC AChE or peripheral AChE. In oral studies, RBC
AChE inhibition is generally similar in response to peripheral tissues.
Thus, the in vitro data and oral studies combined support the continued
use of RBC AChE inhibition as the critical effect for quantitative
dose-response assessment.
For chlorpyrifos, there are data from multiple studies which
provide robust RBC AChE data, including studies in pregnant, lactating,
and non-pregnant female rats from oral exposure (e.g., developmental
neurotoxicity (DNT), reproductive, and subchronic data). In addition,
studies are available in juvenile pups that show age-dependent
differences, particularly following acute exposures, in sensitivity to
chlorpyrifos and its oxon metabolite. This sensitivity is not derived
from differences in the AChE enzyme itself but instead are derived
largely from the immature metabolic clearance capacity in the
juveniles.
b. Neurodevelopmental Toxicity
In addition to information on the effects of chlorpyrifos on AChE,
there is an extensive body of information (in the form of laboratory
animal studies, epidemiological studies, and mechanistic studies)
studying the potential effects on neurodevelopment in infants and
children following exposure to organophosphates, including
chlorpyrifos.
There are numerous laboratory animal studies on chlorpyrifos in the
literature that have evaluated the impact of chlorpyrifos exposure in
pre- and post-natal dosing on the developing brain. These studies vary
substantially in their study design, but all involve gestational and/or
early post-natal dosing with behavioral evaluation from adolescence to
adulthood. The data provide qualitative support for chlorpyrifos to
potentially impact the developing mammalian brain with adverse outcomes
in several neurological domains including cognitive, anxiety and
emotion, social interactions, and neuromotor function. It is, however,
important to note that there is little consistency in patterns of
effects across studies. In addition, most of these studies use doses
that far exceed EPA's 10% benchmark response level for RBC AChE
inhibition. There are only a few studies with doses at or near the 10%
brain or RBC AChE inhibition levels; among these only studies from Carr
laboratory at Mississippi State University are considered by EPA to be
high quality. In the 2020 HH DRA, EPA concluded that the laboratory
animal studies on neurodevelopmental outcomes are not sufficient for
quantitatively establishing a PoD. EPA further concluded that the
laboratory animal studies do not support a conclusion that adverse
neurodevelopmental outcomes are more sensitive than 10% RBC AChE
inhibition. (Ref. 17 at 25-31, Ref. 12 at 88-89).
EPA evaluated numerous epidemiological studies on chlorpyrifos and
other organophosphate pesticides in accordance with the ``Framework for
Incorporating Human Epidemiologic & Incident Data in Health Risk
Assessment.'' (Ref. 17, 18, and 19) The most robust epidemiologic
research comes from three prospective birth cohort studies. These
include: (1) The Mothers and Newborn Study of North Manhattan and South
Bronx performed by the Columbia Children's Center for Environmental
Health (CCCEH) at Columbia University; (2) the Mount Sinai Inner-City
Toxicants, Child Growth and Development Study or the ``Mt. Sinai Child
Growth and Development Study;'' and (3) the Center for Health
Assessment of Mothers and Children of Salinas Valley (CHAMACOS)
conducted by researchers at University of California Berkeley. (Ref. 17
at 32-43).
In the case of the CCCEH study, which specifically evaluated the
possible connections between chlorpyrifos levels in cord blood and
neurodevelopmental outcomes on a specific cohort, there are a number of
notable associations. (Ref. 17 at 36-38) Regarding infant and toddler
neurodevelopment, the CCCEH authors reported statistically significant
deficits of 6.5 points on the Psychomotor Development Index at three
years of age when comparing high to low exposure groups. Notably, these
decrements persist even after adjustment for group and individual level
socioeconomic variables. These investigators also observed increased
odds of mental delay and psychomotor delay at age three when comparing
high to low exposure groups. The CCCEH authors also report strong,
consistent evidence of a positive association for attention disorders,
attention deficit hyperactivity disorder (ADHD), and pervasive
development disorder (PDD) when comparing high to low chlorpyrifos
exposure groups. Moreover, it was reported that for children in the
CCCEH cohort at age seven for each standard deviation increase in
chlorpyrifos cord blood exposure, there is a 1.4% reduction in Full-
Scale IQ and a 2.8% reduction in Working Memory. In addition, the CCCEH
authors evaluated the relationship between pre-natal
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chlorpyrifos exposure and motor development/movement and reported
elevated risks of arm tremor in children around 11 years of age in the
CCCEH cohort.
Notwithstanding the observed associations, EPA and the 2012 and
2016 FIFRA SAP reports identified multiple uncertainties in the CCCEH
epidemiology studies. (Ref. 17 and 20) Some of these include the
relatively modest sample sizes, which limited the statistical power;
exposure at one point in pre-natal time with no additional information
regarding post-natal exposures; representativeness of a single point
exposure where time-varying exposures or the ability to define
cumulative exposures would be preferable; lack of specificity of a
critical window of effect and the potential for misclassification of
individual exposure measures; and lack of availability of the raw data
from the studies that would allow verification of study conclusions.
One of the notable uncertainties in the CCCEH epidemiology studies
identified by EPA and the 2016 FIFRA SAP report is the lack of specific
exposure information on the timing, frequency, and magnitude of
chlorpyrifos application(s) in the apartments of the women in the
study. Since 2012, despite extensive effort by EPA to obtain or infer
this exposure information from various sources, the lack of specific
exposure data remains a critical uncertainty. EPA made efforts in 2014
and 2016 to develop dose reconstruction of the exposures to these
women. These dose reconstruction activities represent the best
available information and tools but are highly uncertain. In addition,
the pregnant women and children in the CCCEH studies were exposed to
multiple chemicals, including multiple potent AChE-inhibiting
organophosphates and N-methyl carbamates. Moreover, using EPA's dose
reconstruction methods from 2014 suggest that the pregnant women likely
did not exhibit RBC AChE inhibition above 10%. The 2012 and 2016 FIFRA
SAP reports expressed concern that it is likely that the CCCEH findings
occurred at exposure levels below those that result in 10% RBC AChE
inhibition. (Ref. 17 and 20) However, given the limitations of the
available CCCEH exposure information and the exposures to multiple
potent AChE inhibiting pesticides, EPA has been unable to definitively
conclude the level of AChE inhibition occurring in the CCCEH studies.
Consistent with the 2016 SAP report, EPA remains unable to make a
causal linkage between chlorpyrifos exposure and the outcomes reported
by CCCEH investigators. (Ref. 12 and 17) Given the uncertainties,
particularly in the exposure information available from CCCEH (single
timepoints, lack of time varying exposure, lack of knowledge about
application timing), uncertainties remain about the dose-response
relationships from the epidemiology studies, which EPA noted in the
2020 HH DRA. (Ref. 12)
Finally, there are several lines of evidence for modes of action of
chlorpyrifos distinct from the classical mode of action of AChE
inhibition. This information has been generated from model systems
representing different levels of biological organization and provide
support for molecular initiating events (binding to the morphogenic
site of AChE, muscarinic receptors, or tubulin), cellular responses
(alterations in neuronal proliferation, differentiation, neurite
growth, or intracellular signaling), and responses at the level of the
intact nervous system (serotonergic tone, axonal transport). Among the
many in vitro studies on endpoints relevant to the developing brain
available for chlorpyrifos, only three have identified outcomes in
picomole concentrations, including concentrations lower than those that
elicit AChE inhibition in vitro. However, as is the case for many other
developmental neurotoxicants, most of these studies have not been
designed with the specific goal of construction or testing an adverse
outcome pathway. Thus, as discussed in the 2020 HHRA, there are not
sufficient data available to test rigorously the causal relationship
between effects of chlorpyrifos at the different levels of biological
organization in the nervous system. (Ref. 17 at 27-31), so until there
are any updates to the state of the science for chlorpyrifos, the
Agency is relying on the 2020 HHRA for this rule.
3. Hazard Identification: Using AChE as the Toxicological Endpoint for
Deriving PADs
In its 2020 HH DRA assessment, based on its review of all available
data, EPA determined that AChE inhibition has the most robust
quantitative dose-response data and, thus, was chosen as the critical
effect for the quantitative risk assessment. The Agency typically uses
a 10% response level for AChE inhibition in human health risk
assessments. This longstanding approach, see 2006 RED, is consistent
with the advice of the FIFRA SAP from 2008 and 2012 and has been
applied in the 2006 OP cumulative risk assessment and other single-
chemical OP risk assessments. (Ref. 21 and 22).
During the ongoing registration review of chlorpyrifos and
consideration of the 2007 Petition, the Agency has received comments
concerning whether the use of the 10% AChE inhibition is sufficiently
health protective. In one effort to take those comments into
consideration, EPA conducted an additional hazard analysis and convened
the 2016 FIFRA SAP to evaluate a proposal of using cord blood data from
the CCCEH epidemiology studies as the source of data for PoDs. The 2016
FIFRA SAP report did not support the ``direct use'' of the cord blood
and working memory data for deriving the regulatory endpoint, due to
insufficient information about timing and magnitude of chlorpyrifos
applications in relation to cord blood concentrations at the time of
birth, uncertainties about the pre-natal window(s) of exposure linked
to reported effects, and lack of a second laboratory to reproduce the
analytical blood concentrations. (Ref. 17) Despite their critiques
regarding uncertainties in the CCCEH studies, the 2016 FIFRA SAP report
expressed concern that 10% RBC AChE inhibition may not be sufficiently
protective of human health.
The 2016 FIFRA SAP report, however, did present an alternative
approach for EPA to consider. This report was supportive of EPA's use
of the PBPK-PD model as a tool for assessing internal dosimetry from
typical pesticide exposure scenarios. Use of the PBPK-PD model coupled
with typical exposure scenarios provides the strongest scientific
foundation for chlorpyrifos human health risk assessment. Given that
the window(s) of susceptibility are currently not known for the
observed neurodevelopmental effects, and the uncertainties associated
with quantitatively interpreting the CCCEH cord blood data, the 2016
FIFRA SAP report recommended that the Agency use a time weighted
average (TWA) blood concentration of chlorpyrifos for the CCCEH study
cohort as the PoD for risk assessment. Thus, in 2016, EPA attempted,
using the PBPK-PD model, to determine the TWA blood level expected from
post-application exposures from the chlorpyrifos indoor crack-and-
crevice use scenario. Despite that effort, EPA concluded in the 2020 HH
DRA that the shortcomings of the data with regard to the dose-response
relationship and lack of exposure information discussed above, continue
to raise issues that make quantitative use of the CCCEH data in risk
assessment not scientifically sound. (Ref. 12)
Thus, taking into consideration the robustness of the available
data at this
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time, EPA has determined in the 2020 HH DRA that the most appropriate
toxicological endpoint for deriving points of departure for assessing
risks of chlorpyrifos is 10% RBC AChE inhibition. The Agency is not
ignoring or dismissing the extensive data concerning the potential for
adverse neurodevelopmental outcomes. As discussed later in this Unit,
the Agency is addressing the uncertainties surrounding the potential
for adverse neurodevelopmental outcomes by retaining the default 10X
FQPA SF.
a. Durations of Exposure
As noted in Unit IV.A.1., EPA establishes PoDs for each expected
exposure duration likely to result from pesticide exposure. For
chlorpyrifos, exposure can occur from a single event or on a single day
or from repeated days of exposure. With respect to AChE inhibition,
effects can occur from a single exposure or from repeated exposures.
For organophosphates, repeated exposures generally result in more AChE
inhibition at a given administered dose compared to acute exposures.
Moreover, AChE inhibition in repeated dosing guideline toxicology
studies with most organophosphates show a consistent pattern of
inhibition reaching a ``steady state'' of inhibition at or around 2 to
3 weeks of exposure in adult laboratory animals. (Ref. 23) This pattern
observed with repeated dosing is a result of the amount of inhibition
coming to equilibrium with production of new enzyme. As such, AChE
studies of 2 to 3 weeks generally show the same degree of inhibition
with those of longer duration (i.e., up to two years of exposure).
Thus, for most of the human health risk assessments for the
organophosphates, the Agency is focusing on the critical durations
ranging from a single day up to 21 days (i.e., the approximate time to
reach steady state for most organophosphates). As such, EPA has
calculated PoDs for the acute and steady-state durations. As described
below, these PoDs have been derived for various lifestages, routes, and
exposure scenarios.
b. Deriving PoDs, Interspecies and Intraspecies Extrapolation: Use of
the PBPK Model
The process for developing RfDs and PADs typically involves first
deriving PoDs directly from laboratory animal studies, followed by
dividing the PoD by the default uncertainty factors of 10X each for
interspecies extrapolation and intraspecies extrapolation, and the FQPA
safety factor. For chlorpyrifos, EPA has developed a sophisticated
PBPK-PD model to derive PoDs. Numerous federal advisory committees and
external review panels have encouraged the use of such a modeling
approach to reduce inherent uncertainty in the risk assessment and
facilitate more scientifically sound extrapolations across studies,
species, routes, and dose levels. The PBPK-PD model for chlorpyrifos
has undergone extensive peer review by various individual or groups,
including the FIFRA SAPs. Significant improvements have been made to
the model over the years in response to recommendations from the 2008,
2011, and 2012 FIFRA SAPs and comments from both internal and external
peer reviewers. (Ref. 12 at 20) As a result, EPA has concluded that the
current PBPK-PD model is sufficiently robust and is using it for
deriving PoDs for chlorpyrifos.
i. Derivation of PoDs
As noted above, the PoDs for chlorpyrifos are based on the levels
at which 10% RBC AChE inhibition is observed. The PBPK-PD model
accounts for pharmacokinetic and pharmacodynamic characteristics to
derive age, duration, and route-specific PoDs. Separate PoDs have been
calculated for dietary (food, drinking water) and residential exposures
by varying inputs on types of exposures and populations exposed.
Specifically, the following characteristics have been evaluated: (1)
Duration (24-hour (acute), 21-day (steady-state)); (2) route (dermal,
oral, inhalation); (3) body weights which vary by lifestage; (4)
exposure duration (hours per day, days per week); and (5) exposure
frequency (events per day (eating, drinking)). For each exposure
scenario, the appropriate body weight for each age group or sex was
modeled as identified from the Exposure Factors Handbook for
residential exposures and from the U.S. Department of Agriculture's
(USDA) National Health and Nutrition Examination Survey (NHANES)/What
We Eat in America (WWEIA) Survey for dietary exposures. (Ref. 24).
Using the PBPK-PD model, the Agency evaluated the following
exposure scenarios: (1) drinking water exposures to oxon (chlorpyrifos
metabolite)--acute and steady-state exposures for infants, children,
youths, and female adults; (2) food exposures to chlorpyrifos--acute
and steady-state exposures for infants, children, youths, and female
adults; (3) residential dermal exposures to chlorpyrifos--steady-state
exposures for children, youths, and female adults; (4) residential
hand-to-mouth ingestion exposures--steady-state for children 1 to 2
years old; and (5) residential inhalation exposures--steady-state for
children 1 to 2 years old and female adults. (Ref. 12 at 22-25).
Steady-state dietary exposure was estimated daily for 21 days. For
drinking water exposure, infants and young children (infants <1 year
old, children between 1 to 2 years old, and children between 6 to 12
years old) were assumed to consume water 6 times per day, with a total
consumption volume of 0.69 L/day. For youths and female adults, they
were assumed to consume water 4 times per day, with a total consumption
volume of 1.71 L/day.
For all residential dermal exposures to chlorpyrifos, the dermal
PoDs were estimated assuming 50% of the skin's surface was exposed.
Exposure times for dermal exposure assessment were consistent with
those recommended in the 2012 Residential Standard Operating Procedures
(SOPs). (Ref. 22) For residential inhalation exposures following public
health mosquitocide application, the exposure duration was set to 1
hour per day for 21 days. The incidental oral PoDs for children 1 to <2
years old for other turf activities were estimated assuming that there
were six events, 15 minutes apart, per day.
The PBPK-modeled PoDs derived for the various lifestages, routes,
and exposure scenarios discussed above, can be found in table 4.2.2.1.2
of the 2020 HH DRA. (Ref. 12).
ii. Interspecies Extrapolation
As indicated above, the PBPK-PD model directly predicts human PoDs
based on human physiology and biochemistry; thus, there is no need for
an interspecies uncertainty factor to extrapolate from animal PoDs.
iii. Intraspecies Extrapolation
The PBPK-PD model can account for variability of critical
physiological, pharmacokinetic, and pharmacodynamic parameters in a
population to estimate, using the Monte Carlo analysis, the
distribution of doses that result in 10% RBC AChE inhibition.
Therefore, Data-Derived Extrapolation Factors (DDEF) for intraspecies
extrapolation have been estimated to replace the default intraspecies
uncertainty factor for some groups. (Ref. 25).
According to EPA's DDEF guidance, when calculating a DDEF
intraspecies extrapolation factor, administered doses leading to the
response level of interest (in the case of chlorpyrifos, the 10% change
in RBC AChE inhibition) are compared between a measure of average
response and response at the tail of the distribution representing
sensitive individuals. The tail of the distribution
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may be selected at the 95th, 97.5th, and 99th percentile.
As for chlorpyrifos, the 99th percentile was used in risk
assessment to provide the most conservative measure. (Ref. 26) In
addition to estimating DDEF using the above approach for specific age
groups, intraspecies DDEF were also calculated by comparing average
responses between adults and 6-month-old infants. For the 2020 HHRA,
the largest calculated DDEFs, 4X for chlorpyrifos and 5X for the oxon
metabolite, were used for intraspecies extrapolation for all groups
except women of childbearing age. There was a slightly higher
variability between adults and infants when considering the
distributions for the oxon metabolite, thus, the slightly higher
intraspecies factor. For women of childbearing age, the Agency is
applying the standard 10X intraspecies extrapolation factor due to
limitations in the PBPK-PD model to account for physiological,
anatomical, and biochemical changes associated with pregnancy. (Ref. 12
at 21-22).
iv. Summarizing the PoDs, Interspecies and Intraspecies Extrapolation
Factors
In summary, for assessing the risks from exposure to chlorpyrifos,
the human PBPK-PD model has been used to derive PoDs based on 10% RBC
AChE inhibition for various populations, durations, and routes. The
model, which calculates a human PoD directly, obviates the need for an
interspecies extrapolation factor since animal data are not used. To
account for variations in sensitivities, the Agency has determined that
an intraspecies factor of 4X for chlorpyrifos and 5X for the oxon is
appropriate for all groups except women of childbearing age. For women
of childbearing age, the typical 10X intraspecies factor is being
applied, due the lack of appropriate information and algorithms to
characterize physiological changes during pregnancy.
c. FQPA Safety Factor
As noted above, the FFDCA requires EPA, in making its safety
finding, that in ``the case of threshold effects, an additional tenfold
margin of safety for the pesticide chemical residue and other sources
of exposure shall be applied for infants and children to take into
account potential pre- and post-natal toxicity and completeness of data
with respect to exposure and toxicity to infants and children.'' 21
U.S.C. 346a(b)(2)(C). Section 408(b)(2)(C) further states that ``the
Administrator may use a different margin of safety for the pesticide
chemical residue only if, on the basis of reliable data, such margin
will be safe for infants and children.'' Id.
In applying the FQPA SF provision, EPA has interpreted it as
imposing a presumption in favor of retaining it as an additional 10X
SF. (Ref. 27 at 4, 11) Thus, EPA generally refers to the 10X factor as
a presumptive or default 10X factor. EPA has also made clear, however,
that this presumption or default in favor of the 10X is only a
presumption. The presumption can be overcome if reliable data
demonstrate that a different factor is safe for children. (Id.). In
determining whether a different factor is safe for children, EPA
focuses on the three factors listed in FFDCA section 408(b)(2)(C)--the
completeness of the toxicity database, the completeness of the exposure
database, and potential pre- and post-natal toxicity. In examining
these factors, EPA strives to make sure that its choice of a SF, based
on a weight-of-the-evidence evaluation, does not understate the risk to
children. (Id. at 24-25, 35).
In the 2020 HH DRA, the default 10X FQPA SF was retained, and the
assessment did not adopt or offer support for reducing the factor to
1X. However, the 2020 HH DRA does present potential risks from
exposures to chlorpyrifos with retention of the default 10X FQPA SF and
with reduction of the FQPA SF to 1X. The purpose of presenting both
values was to provide an indication of what the potential risk
estimates would be under either scenario. To reduce the FQPA SF to 1X,
the FFDCA requires that EPA determine that reliable data demonstrate
that the 1X would be safe for infants and children. The 2020 HH DRA did
not make that determination. For chlorpyrifos, of the three factors
mentioned in the previous paragraph, the primary factor that undercuts
a determination that a different SF would be safe for children is the
uncertainty around the potential for pre- and post-natal toxicity for
infants and children in the area of neurodevelopmental outcomes.
Based on the weight of the evidence concerning the potential for
neurodevelopmental outcomes as discussed in this Unit above, there is
ample qualitative evidence of a potential effect on the developing
brain; however, there remains uncertainty around the levels at which
these potential neurodevelopmental outcomes occur. Although the
laboratory animal studies do not support a conclusion that
neurodevelopmental outcomes are more sensitive than AChE inhibition,
there remains some uncertainty in the dose-response relationship
between chlorpyrifos and adverse neurodevelopmental outcomes based on
the epidemiology data, and the mechanistic data are, at this time,
incomplete in their characterization of dose-response. Because the data
available at this time indicate remaining uncertainties concerning pre-
and post-natal toxicity due to insufficient clarity on the levels at
which these outcomes occur, the Agency is unable to conclude, at this
time, that a different SF would be safe for infants and children. Thus,
the Agency is retaining the default 10X FQPA SF at this time.
d. Total Uncertainty Factors and PADs
In conclusion, the Agency used a total uncertainty factor of 100X
for determining the food and drinking water PADs for females of
childbearing age (1X interspecies factor, 10X intraspecies factor, and
10X FQPA SF); 40X for determining the food PADs for remaining
populations (1X interspecies factor, 4X intraspecies factor, and 10X
FQPA SF); and 50X for determining the PADs for drinking water for
remaining populations (1X interspecies factor, 5X intraspecies factor,
and 10X FQPA SF).
Taking into consideration the PoDs, intraspecies extrapolation
factors, and FQPA SF, the Agency calculated acute PADs (aPADs) and
steady-state PADs (ssPADs) for infants (less than 1 year old), children
(1 to 2 years old), children/youth (6 to 12 years old), and females (13
to 49 years old); these subpopulations will be protective of other
subpopulations. While PADs were calculated for youths (13 to 19 years
old), these PADs were not used in the dietary/aggregate assessments
because females (13 to 49 years old) are considered protective of this
sub-population. (Ref. 12 at 30-32) Risk estimates can be found in table
5.0.1 in the 2020 HH DRA.
B. EPA's Exposure Assessment for Chlorpyrifos
Risk is a function of both hazard and exposure. Thus, equally
important to the risk assessment process as determining the hazards
posed by a pesticide and the toxicological endpoints for those hazards
is estimating human exposure. Under FFDCA section 408, EPA must
evaluate the aggregate exposure to a pesticide chemical residue, which
includes ``all anticipated dietary exposures and all other exposures
for which there is reliable information.'' 21 U.S.C. 346a(b)(2)(A)(ii).
This means that EPA is concerned not only with exposure to pesticide
residues in food but also exposure resulting from pesticide
contamination of drinking water
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supplies and from use of pesticides in the home or other non-
occupational settings. (See 21 U.S.C. 346a(b)(2)(D)(vi)).
Pursuant to FFDCA section 408(b), EPA has evaluated chlorpyrifos's
risks based on ``aggregate exposure'' to chlorpyrifos. By ``aggregate
exposure,'' EPA is referring to exposure to chlorpyrifos by multiple
pathways of exposure, i.e., food, drinking water, and residential. EPA
uses available data and standard analytical methods, together with
assumptions designed to be protective of public health, to produce
separate estimates of exposure for a highly exposed subgroup of the
general population, for each potential pathway and route of exposure.
The following analysis reflects a summary of the Agency's exposure
assessment from the 2020 HH DRA unless otherwise specified. (Ref. 2).
1. Exposure From Food
a. General Approach for Estimating Food Exposures
There are two critical variables in estimating exposure in food:
(1) the types and amount of food that is consumed; and (2) the residue
level in that food. Consumption is estimated by EPA based on scientific
surveys of individuals' food consumption in the United States conducted
by the U.S. Department of Agriculture (USDA). (Ref. 28 at 12)
Information on residue values can come from a range of sources
including crop field trials; data on pesticide reduction (or
concentration) due to processing, cooking, and other practices;
information on the extent of usage of the pesticide; and monitoring of
the food supply. (Id. at 17).
Data on the residues of chlorpyrifos in foods are available from
both field trial data and monitoring data, primarily the USDA's
Pesticide Data Program (PDP) monitoring data. Monitoring data generally
provide a characterization of pesticide residues in or on foods
consumed by the U.S. population that closely approximates real-world
exposures because they are sampled closer to the point of consumption
in the chain of commerce than field trial data, which are generated to
establish the maximum level of legal residues that could result from
maximum permissible use of the pesticide immediately after harvest.
EPA used a computer program known as the Dietary Exposure
Evaluation Model and Calendex software with the Food Commodity Intake
Database (DEEM-FCID version 3.16/Calendex) to estimate chlorpyrifos
exposure by combining data on human consumption amounts with residue
values in food commodities. This version of the model incorporated
2003-2008 consumption data from USDA's NHANES/WWEIA. The data are based
on the reported consumption of more than 20,000 individuals over two
non-consecutive survey days. Foods ``as consumed'' (e.g., apple pie)
are linked to EPA-defined food commodities (e.g., apples, peeled
fruit--cooked; fresh or N/S (Not Specified); baked; or wheat flour--
cooked; fresh or N/S, baked) using publicly available recipe
translation files developed jointly by USDA Agricultural Research
Service (ARS) and EPA. For chronic exposure assessment (or in the case
of chlorpyrifos, for steady-state exposure assessment), consumption
data are averaged for the entire U.S. population and within population
subgroups; however, for acute exposure assessment, consumption data are
retained as individual consumption events. Using this consumption
information and residue data, the exposure estimates are calculated for
the general U.S. population and specific subgroups based on age, sex,
ethnicity, and region.
For chlorpyrifos, EPA determined that acute and steady-state
exposure durations were relevant for assessing risk from food
consumption. EPA calculates potential risk by using probabilistic
techniques to combine distributions of potential exposures in sentinel
populations. The resulting probabilistic assessments present a range of
dietary exposure/risk estimates.
Because probabilistic assessments generally present a realistic
range of residue values to which the population may be exposed, EPA's
starting point for estimating exposure and risk for such assessments is
the 99.9th percentile of the population under evaluation. When using a
probabilistic method of estimating acute dietary exposure, EPA
typically assumes that, when the 99.9th percentile of acute exposure is
equal to or less than the aPAD, the level of concern for acute risk has
not been exceeded. By contrast, where the analysis indicates that
estimated exposure at the 99.9th percentile exceeds the aPAD, EPA would
generally conduct one or more sensitivity analyses to determine the
extent to which the estimated exposures at the high-end percentiles may
be affected by unusually high food consumption or residue values. (The
same assumptions apply to estimates for steady-state dietary exposure
and the ssPAD.) To the extent that one or a few values seem to
``drive'' the exposure estimates at the high-end of exposure, EPA would
consider whether these values are reasonable and should be used as the
primary basis for regulatory decision making. (Ref. 29).
b. Estimating Chlorpyrifos Exposures in Food
The residue of concern, for tolerance expression and risk
assessment, in plants (food and feed) and livestock commodities is the
parent compound chlorpyrifos. EPA has determined that the metabolite
chlorpyrifos oxon is not a residue of concern in food or feed, based on
available field trial data and metabolism studies that indicate that
the oxon is not present in the edible portions of the crops. This
conclusion is supported by USDA PDP monitoring data, which did not find
residues of chlorpyrifos oxon on food samples. Furthermore, the oxon
metabolite was not found in milk or livestock tissues. (Ref. 12 at 33).
Acute and steady-state dietary (food only) exposure analyses for
chlorpyrifos were conducted using the DEEM-FCID version 3.16/Calendex
software. (Ref. 30) These analyses were performed for the purpose of
obtaining food exposure values for comparison to the chlorpyrifos doses
predicted by the PBPK-PD model to cause 10% RBC AChE inhibition. The
acute and steady-state dietary (food only) exposure analyses do not
include drinking water exposures, which were assessed separately, as
discussed in the next section.
The assessments include exposures to residues on all field crops
and livestock use resulting from uses registered at the time of the
dietary risk assessment as well as residues on imported commodities,
but the assessments do not include potential exposure from food
handling establishments as those were considered negligible. (Ref. 26)
Both the acute and steady-state dietary (food only) exposure analyses
are highly refined. The large majority of food residues used were based
upon PDP monitoring data except in a few instances where no appropriate
PDP data were available. In those cases, field trial data or tolerance-
level residues were assumed. EPA also used food-processing factors from
submitted studies as appropriate. In addition, EPA's acute and steady-
state dietary (food only) exposure assessments used percent crop
treated (PCT) information. (Ref. 30).
The chlorpyrifos acute dietary (food only) exposure analysis was
conducted using the DEEM-FCID, version 3.16. The acute risk estimates
were presented for the sentinel populations for infants (less than 1
year old); children (1-2 years old); youths (6-12 years old); and
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adults (females 13-49 years old). The assessment of these index
lifestages is protective of other population subgroups.
The chlorpyrifos steady-state dietary (food only) exposure analysis
was conducted using the Calendex component of DEEM-FCID (with 2003-2008
survey consumption data from USDA's NHANES/WWEIA). Calendex provides a
focus detailed profile of potential exposures to individuals across a
calendar year. A calendar-based approach provides the ability to
estimate daily exposures from multiple sources over time to an
individual and is in keeping with two key tenets of aggregate risk
assessment: (1) that exposures when aggregated are internally
consistent and realistic; and (2) that appropriate temporal and
geographic linkages or correlations/associations between exposure
scenarios are maintained.
The chlorpyrifos steady-state dietary (food only) assessment
considers the potential risk from a 21-day exposure duration using a 3-
week rolling average (sliding by day) across the year. For this
assessment, the same food residue values used in the acute assessment
were used for the 21-day duration. In the Calendex software, one diary
for each individual in the WWEIA is selected to be paired with a
randomly selected set of residue values for each food consumed. The
steady-state analysis calculated exposures for the sentinel populations
for infants (less than 1 year old); children (1 to 2 years old); youths
(6 to 12 years old); and adults (females 13 to 49 years old). The
assessment of these index lifestages is protective of other population
subgroups.
2. Exposure From Drinking Water
a. General Approach for Assessing Exposure From Drinking Water
i. Modeling and Monitoring Data
Monitoring and modeling are both important tools for estimating
pesticide concentrations in water and can provide different types of
information. Monitoring data can provide estimates of pesticide
concentrations in water that are representative of the specific
agricultural or residential pesticide practices in specific locations,
under the environmental conditions associated with a sampling design
(i.e., the locations of sampling, the times of the year samples were
taken, and the frequency by which samples were collected). Although
monitoring data can provide a direct measure of the concentration of a
pesticide in water, it does not always provide a reliable basis for
estimating spatial and temporal variability in exposures because
sampling may not occur in areas with any pesticide use, with the
highest pesticide use, when the pesticides are being used, and/or at an
appropriate sampling frequency to detect high concentrations of a
pesticide that occur over the period of a day to several days.
Because of the limitations in most monitoring studies, EPA's
standard approach is to use water exposure models as the primary means
to estimate pesticide exposure levels in drinking water. Modeling is a
useful tool for characterizing vulnerable sites and can be used to
estimate upper-end pesticide water concentrations in surface water and
groundwater. EPA's computer models use detailed information on soil
properties, crop characteristics, and weather patterns to estimate
water concentrations in vulnerable locations where the pesticide could
be used according to its label. (Ref. 31 at 27-28) EPA's models
calculate estimated water concentrations of pesticides using laboratory
data that describe how fast the pesticide breaks down to other
chemicals and how it moves in the environment at these vulnerable
locations. Depending on the modeling algorithm (e.g., surface water
modeling scenarios), daily concentrations can be estimated continuously
over long periods of time, and for places that are of most interest for
any particular pesticide.
EPA relies on models it has developed for estimating pesticide
concentrations in both surface water and ground water. The most common
model used to conduct drinking water assessments is the Pesticide in
Water Calculator (PWC). PWC couples the Pesticide Root Zone Model
(PRZM) and Variable Volume Water Model (VVWM) together to simulate
pesticide fate and transport from the field of application to an
adjacent reservoir. (Ref. 31 at 27-28). The PWC estimates pesticide
concentrations for an index reservoir that is modeled for site-specific
scenarios (i.e., weather and soil data) in different areas of the
country. A detailed description of the models routinely used for
exposure assessment is available from the EPA OPP Aquatic Models
website. See EPA's aquatic models for estimating pesticide
concentrations in food, water, non-target organisms, and residential
and occupational environments. (Ref. 2).
In modeling potential surface water concentrations, EPA models
areas of the country that are vulnerable to surface water
contamination. Consequently, EPA models exposures occurring in small
highly agricultural watersheds in different growing areas throughout
the country, over a 30-year period. The scenarios are designed to
capture residue levels in drinking water from reservoirs with small
watersheds with a large percentage of land use in agricultural
production. EPA believes these assessments are likely reflective of a
small subset of watersheds across the country and represent a drinking
water source generally considered to be the most vulnerable to frequent
high concentrations of pesticides.
When monitoring data meet certain data quantity criteria, EPA has
tools available to quantify the uncertainty in available monitoring
data such that it can be used quantitively to estimate pesticide
concentrations in drinking water. (Ref. 32) Furthermore, monitoring
data can be used in a weight of evidence approach with model estimated
concentrations to increase confidence in the conclusions of a drinking
water assessment.
ii. Drinking Water Level of Comparison (DWLOC)
The drinking water level of comparison (DWLOC) is a benchmark that
can be used to guide refinements of the DWA. For a drinking water
assessment that utilizes a DWLOC, the calculated DWLOC is compared to
the EDWC. When the EDWC is greater than the DWLOC, there may be a risk
concern. Conversely, when the EDWC is less than the DWLOC, there are no
risks of concern.
The DWLOC relates to the concept of the ``risk cup,'' which EPA
developed to facilitate risk refinement when considering aggregate
human health risk to a pesticide. (Ref. 33) The risk cup is the total
exposure allowed for a pesticide considering its toxicity and required
safety factors. The risk cup represents the maximum safe exposure for
the duration and population being considered. Exposures exceeding the
risk cup are of potential concern. There are risk cups for each
pertinent duration of exposure (e.g., acute, short-term, chronic). For
chlorpyrifos, EPA is using exposure durations of acute (single day, 24
hours) and steady state (21-day). (Ref. 32).
In practice, EPA calculates the total exposure from food
consumption and residential (or other non-occupational) exposures and
subtracts this value from the maximum safe exposure level. The
resulting value is the allowable remaining exposure that can come from
drinking water without the potential for adverse health effects.
Knowing this allowable remaining exposure and the water consumption for
each population
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subgroup (e.g., infants), the Agency can calculate the DWLOC, which is
the estimate of safe concentration of pesticides in drinking water.
Using this process of DWLOC calculation allows EPA to determine a
target maximum safe drinking water concentration, thereby identifying
instances where drinking water estimates require refinement or
estimates that may be indicative of risk. (Ref. 31 at 19-20).
iii. Scale of Drinking Water Assessment
Although food is distributed nationally and pesticide residue
values on food are therefore not expected to vary substantially
throughout the country, drinking water is locally derived and
concentrations of pesticides in source water fluctuate over time and
location for a variety of reasons. Pesticide residues in water
fluctuate daily, seasonally, and yearly because of the timing of the
pesticide application, the vulnerability of the water supply to
pesticide loading through runoff, spray drift and/or leaching, and
changes in the weather. Concentrations are also affected by the method
of application, the location, and characteristics of the sites where a
pesticide is used, the climate, and the type and degree of pest
pressure, which influences the application timing, rate used, and
number of treatments in a crop production cycle.
EPA may conduct a DWA for a national scale depending on the
pesticide use under evaluation. A national scale DWA may use a single
upper-end pesticide concentration as a starting point for assessing
whether additional refinements are needed or estimated pesticide
concentrations for certain site-specific scenarios that are associated
with locations in the United States vulnerable to pesticide
contamination based on pesticide use patterns. (Ref. 31 at 22).
EPA may also conduct a regional scale DWA to focus on areas where
pesticide concentrations may be higher than the DWLOC. Under this
assessment, EPA estimates pesticide concentrations across different
regions in the United States that are subdivided into different areas
called hydrologic units, identified by a two-digit hydrologic unit code
(HUC 2) number. There are 21 HUC 2 regions in the United States, with
18 of them within the contiguous United States. These areas contain
either the drainage area of a major river or a combined drainage of a
series of rivers. See United States Geological Survey (USGS) Water
Resources of the United States. (Ref. 34) Estimated pesticide
concentrations under this approach would be associated with a
vulnerable pesticide use area somewhere within the evaluated region.
(Ref. 31 at 23).
iv. Drinking Water Refinements
EPA has defined four assessment tiers for drinking water
assessments. Lower-tiered assessments are more conservative based on
the defaults or upper bound assumptions and may compound conservatisms,
while higher tiers integrate more available data and provide more
realistic estimates of environmental pesticide concentrations.
These four tiers vary in the level of resources, the amount of data
considered, the spatial scale, and the refinement in the estimated
pesticide concentration. Tier 1 requires the least amount of resources
and the least amount of data, whereas Tier 4 is resource intensive,
considers a wide range of sources and types of data, and is spatially
explicit, resulting in high confidence in the reported pesticide
concentration. Each successive tier integrates more focused pesticide,
spatial, temporal, agronomic, and crop-specific information. The order
in which refinements are considered (i.e., the order in which the
assessment is refined) is pesticide-specific and depends on the nature
and quality of the available data used to support the refinement.
Additional information on the conduct of drinking water assessments can
be found in the ``Framework for Conducting Pesticide Drinking Water
Assessment for Surface Water'' (USEPA, 2020) (``DWA Framework
document''). (Ref. 31).
As discussed in the DWA Framework document, EPA can incorporate
several refinements in higher tiered modeling. Two such refinements are
the percent cropped area (PCA) and the PCT. These are described in the
document titled ``Integrating a Distributional Approach to Using
Percent Crop Area (PCA) and Percent Crop Treated (PCT) into Drinking
Water Assessment.'' (Ref. 35) The PCA refers to the amount of area in a
particular community water system that is planted with the crop of
interest (e.g., the default assumption is that the entire watershed is
planted with a crop of interest). The PCT refers to the amount of the
cropped area that is treated with the pesticide of interest (e.g., the
default is that the entire cropped area is treated with the pesticide
of interest). With additional use and usage data, EPA can refine
assumptions about the application rate and PCT for use in modeling to
generate EDWCs that are appropriate for human health risk assessment
and more accurately account for the contribution from individual use
patterns in the estimation of drinking water concentrations.
b. Drinking Water Assessment for Chlorpyrifos
For the chlorpyrifos drinking water assessment, the metabolite
chlorpyrifos oxon--which forms during water treatment, e.g.,
chlorination, of source water containing chlorpyrifos and is more toxic
than chlorpyrifos--was selected as the residue of concern. (Ref. 36 and
37) The range of conversion from parent to oxon depends upon the type
of water treatment and other conditions. Based on available information
regarding the potential effects of certain water treatments (e.g.,
chlorination appears to hasten transformation of chlorpyrifos-to-
chlorpyrifos oxon), EPA assumed that all chlorpyrifos in source water
is converted to chlorpyrifos oxon upon treatment.
The Agency used a DWLOC approach for assessing aggregate risk from
chlorpyrifos. EPA calculated DWLOCs for different age groups for both
the acute aggregate assessment and the steady-state aggregate
assessment, taking into consideration the food and residential
contributions to the risk cup. These numbers were provided as a
benchmark for evaluating drinking water contributions from uses of
chlorpyrifos across the United States, and whether such concentrations
would result in aggregate exposures to chlorpyrifos that exceeded the
Agency's levels of concern. The lowest acute DWLOC calculated was for
exposure to chlorpyrifos oxon to infants (<1 year old) at 23 ppb; the
lowest steady-state DWLOC calculated was also for exposure to
chlorpyrifos oxon to infants (<1 year old) at 4.0 ppb. (Ref. 12 at 45)
In other words, EDWCs for infants of chlorpyrifos oxon greater than 23
ppb from a single exposure or 4.0 ppb for a 21-day average would exceed
EPA's DWLOC and present a risk that exceeds the Agency's level of
concern.
In its 2014 DWA, EPA concluded that there were multiple uses of
chlorpyrifos that could lead to exposures to chlorpyrifos oxon in
drinking water that exceed the DWLOC. (Ref. 38) The 2014 DWA provided
the basis for the Agency's proposal to revoke tolerances in 2015. (Ref.
39) In 2016, EPA conducted a refined DWA that estimated drinking water
concentrations based on modeling of all registered uses, as well as all
available surface water monitoring data. That 2016 DWA considered
several refinement strategies in a two-step process to derive exposure
estimates for chlorpyrifos and chlorpyrifos oxon across the country.
The first step was an assessment of
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potential exposure based on the current maximum label rates at a
national level. This indicated that the EDWCs could be above the DWLOC.
Because estimated concentrations at the national level exceeded the
DWLOC, the Agency conducted a more refined assessment of uses on a
regional level. (Ref. 36 at 73-86) This more refined analysis derived
EDWCs using the PWC modeling for maximum labeled rates and 1 pound per
acre by region for each use. The analysis indicated that approved uses
of chlorpyrifos in certain vulnerable watersheds in every region of the
country would result in EDWCs that exceed the DWLOC. For example, table
25 of EPA's 2016 DWA, which provides the range of estimated
concentrations of chlorpyrifos in drinking water from uses on golf
courses and agricultural or production crops, shows EDWCs that exceed
the DWLOC in vulnerable watersheds in every region in the country.
While the lower end of some of the ranges provided in that table are
below the DWLOC, those lower numbers reflect a single use (i.e., single
crop) and do not reflect potential exposure from other uses where
applications occur at higher rates, more frequently, or in more
locations made more vulnerable due to soil type, weather, or agronomic
practices--all of which were permitted by labeling that was approved at
that time. The relevant estimated concentration for risk assessment
purposes was the highest concentration across all uses because it
reflects concentrations that may occur in vulnerable sources of
drinking water based on approved use instructions. (Ref. 36 at 73-74).
In addition, a robust quantitative analysis of the monitoring data
was conducted resulting in concentrations consistent with model-
estimated concentrations above the DWLOC. (Ref. 36 at 90-121)
Considering both monitoring data and modeling estimates together
supported the conclusion that drinking water concentrations in regions
across the country exceeded the DWLOC. (Ref. 36 at 121-123).
After the EPA's 2016 DWA showed that the DWLOC exceedances are
possible from several uses, EPA developed refinement strategies to
examine those estimated regional/watershed drinking water
concentrations to pinpoint community drinking water systems where
exposure to chlorpyrifos oxon as a result of chlorpyrifos applications
may pose an exposure concern. At that time, it was anticipated that a
more refined drinking water assessment might allow EPA to better
identify where at-risk watersheds are located throughout the country to
support more targeted risk mitigation through the registration review
process. The refinements better account for variability in the use area
treated within a watershed that may contribute to a drinking water
intake (referred to as PCA or percent use area when considering non-
agricultural uses) and incorporate data on the amount of a pesticide
that is actually applied within a watershed for agricultural and non-
agricultural uses (referred to as PCT). These refinement approaches
underwent external peer review and were issued for public comment in
January 2020. (Ref. 39 and 40) In addition, EPA used average
application rates, average numbers of annual applications for specific
crops, and estimated typical application timing at the state-level
based on pesticide usage data derived from a statistically reliable
private market survey database, publicly available survey data
collected by the USDA, and state-specific scientific literature from
crop extension experts. (Ref. 1)
The refinements were integrated in the 2020 DWA. The updated
assessment applied the new methods for considering the entire
distribution of community water systems, PCA adjustment factors,
integrated state level PCT data, incorporated refined usage and
application data, and included quantitative use of surface water
monitoring data in addition to considering state level usage rate and
data information. In addition, given the 2016 DWA calculation of EDWCs
exceeding the DWLOC of 4.0 ppb, the Agency decided to focus its
refinements for the 2020 DWA on a subset of uses in specific regions of
the United States. The purpose of the focus on this subset of uses was
to determine if limiting use of chlorpyrifos to only certain food uses
and regions would yield EDWCs below the DWLOC. The subset of uses
assessed were selected because they were identified as critical uses by
the registrant and/or high benefit uses to growers. That subset of
registered uses included the 11 identified crops in the specific
geographical areas listed in Unit III, and the assessment of those uses
assumed application rate and timing/frequency restrictions based on
available usage data as described in the previous paragraph. The
results of this analysis indicated that the EDWCs from this limited
subset of uses are below both the acute and chronic DWLOCs. (Ref. 2 at
16-17) The 2020 DWA refined estimates did not include chlorpyrifos
exposures from uses beyond that subset and expressly noted that a
separate assessment would be needed in order to evaluate whether other
uses could be added to or substituted for the crops and areas already
identified and still maintain concentrations below the DWLOC.
3. Residential Exposure to Pesticides
a. General Approach to Assessing Residential Exposures
Residential assessments examine exposure to pesticides in non-
occupational or residential settings (e.g., homes, parks, schools,
athletic fields or any other areas frequented by the general public),
based on registered uses of the pesticide. Exposures to pesticides may
occur to persons who apply pesticides (which is referred to as
residential handler exposure) or to persons who enter areas previously
treated with pesticides (which is referred to as post-application
exposure). Such exposures may occur through oral, inhalation, or dermal
routes and may occur over different exposure durations (e.g., short-
term, intermediate-term, long-term), depending on the type of pesticide
and particular use pattern.
Residential assessments are conducted through examination of
significant exposure scenarios (e.g., children playing on treated lawns
or homeowners spraying their gardens) using a combination of generic
and pesticide-specific data. EPA has prepared SOPs for conducting
residential assessments on a wide array of scenarios that are intended
to address the most common uses by which individuals could be exposed
to pesticides in a non-occupational environment. (Ref. 22) The SOPs
identify relevant generic data and construct algorithms for calculating
exposure amounts using these generic data in combination with
pesticide-specific information. The generic data generally involve
survey data on behavior patterns (e.g., activities conducted on turf
and time spent on these activities) and transfer coefficient data.
Transfer coefficient data measure the amount of pesticide that
transfers from the environment to humans from a defined activity (e.g.,
hand contact with a treated surface or plant). Specific information on
pesticides can include information on residue levels as well as
information on environmental fate such as degradation data.
Typically, once EPA assesses potential exposures from all
applicable exposure scenarios, EPA selects the highest exposure
scenario for each exposed lifestage to calculate representative risk
estimates for use in the aggregate exposure assessment.
[[Page 99199]]
Those specific exposure values are then combined with the lifestage
appropriate exposure values provided for food and drinking water to
determine whether a safety finding can be made. As described above,
since EPA used a DWLOC approach for assessing risks for chlorpyrifos,
EPA combined food exposures covered by all chlorpyrifos tolerances with
residential exposures to identify the DWLOC and compared the DWLOC to
EDWCs to determine whether a safety finding could be made. The end
result is the same since both methods aggregate food, drinking water,
and residential exposure estimates to determine whether a safety
finding can be made.
b. Residential Exposure Assessment for Chlorpyrifos
Most chlorpyrifos products registered for residential treatment
were voluntarily cancelled or phased out by the registrants between
1997 and 2001; however, some uses of chlorpyrifos remain that may
result in non-occupational, non-dietary (i.e., residential) exposures,
specifically roach bait products, fire ant mound treatments, and uses
on golf courses. The roach bait product is designed such that the
active ingredient is contained within a bait station, which eliminates
the potential for contact with the chlorpyrifos containing bait
material; therefore, residential exposures from the roach bait product
were determined to be negligible. Since the ant mound treatments can
only be applied professionally and direct exposure with treated mounds
is not anticipated, residential exposures from the ant mound use were
also determined to be negligible. (Ref. 12 at 36-44).
For the golf course use, the Agency does not anticipate residential
handler exposures, although there is a potential for residential post-
application exposures that would aggregate with dietary exposures from
the registered use on golf courses. Based on the anticipated use
patterns reviewed under the SOP, EPA assessed these exposures as
steady-state residential post-application exposures, which would be
protective of shorter durations of exposure. There is a potential for
dermal post-application exposures from the golf course uses for adults
(females 13 to 49 years old); youths (11 to less than 16 years old);
and children (6 to less than 11 years old). Although EPA did not
identify any post-application risks of concern from use on golf
courses, EPA used the post-application exposures and risk estimates
resulting from the golfing scenarios in EPA's aggregate exposure and
risk assessment.
4. Cumulative Risk
FFDCA section 408(b)(2)(D)(v), 21 U.S.C. 346a(b)(2)(D)(v), requires
EPA to consider ``available information concerning the cumulative
effects of [pesticide chemical] residues and other substances that have
a common mechanism of toxicity.''
Chlorpyrifos belongs to a class of pesticides called
organophosphates (OPs), which share the ability to inhibit AChE through
phosphorylation of the serine residue on the enzyme leading to
accumulation of acetylcholine and ultimately cholinergic neurotoxicity.
This shared mode of action/adverse outcome pathway (MOA/AOP) is the
basis for the OP common mechanism grouping per OPP's Guidance for
Identifying Pesticide Chemicals and Other Substances that have a Common
Mechanism of Toxicity (USEPA, 1999). The 2006 cumulative risk
assessment for organophosphates (2006 OP CRA) used brain AChE
inhibition in female rats as the source of dose response data for the
relative potency factors and PODs for each OP, including chlorpyrifos.
After considering the potential for cumulative risks of concern from
the OPs, EPA concluded that the tolerances were safe. (Ref. 21).
After completion of the single-chemical OP assessments for this
round of registration review, but prior to the issuance of a final
registration review decision for chlorpyrifos (and the other OPs), EPA
will determine whether any updates to the 2006 OP CRA on AChE
inhibition are necessary. In the meantime, no additional uses have been
approved since that document was completed (i.e., no additional
exposures), and many uses have been (or are in the process of being)
cancelled or reduced (e.g., the current reduction of chlorpyrifos
uses). As such, EPA expects the potential for cumulative risks and any
cumulative risk estimates will likely be lower than assessed in 2006,
when EPA concluded that the results of the cumulative assessment
support a reasonable certainty of no harm finding as required by FQPA.
C. Aggregate Risk Assessment and Determination of Safety for
Chlorpyrifos
The final step in the risk assessment is the aggregate exposure
assessment and risk characterization. In this step, EPA combines
information from the first three steps (hazard identification, level of
concern (LOC)/dose-response analysis, and human exposure assessment) to
quantitatively estimate the risks posed by a pesticide. The aggregated
exposure assessment process considers exposure through multiple
pathways or routes of exposure (e.g., food, water, and residential) for
different sub-populations (e.g., infants, children ages 1-2) and
exposure duration or types of effects (e.g., acute (single dose)
noncancer effects, chronic noncancer effects, and cancer). The
aggregated exposure assessments can be deterministic (levels of
exposure for each pathway are point estimates), probabilistic (levels
of exposure are a distribution for a given population), or a
combination of the two and are dependent on the level of refinement or
assessment tier.
As noted above, EPA evaluates aggregate exposure by comparing
combined exposure from all relevant sources to the safe level. Where
exposures exceed the safe level (i.e., the risk cup), they present
potential risks of concern. There are risk cups for each pertinent
duration of exposure for a pesticide because the amount of exposure
that can be incurred without adverse health effects will vary by
duration (e.g., acute, short-term, chronic).
Whether risks will exceed the risk cup (i.e., whether exposures are
expected to exceed safe levels) is expressed differently, depending on
the type of level of concern the Agency has identified. For dietary
assessments, the risk is expressed as a percentage of the acceptable
dose (i.e., the dose which EPA has concluded will be ``safe''). Dietary
exposures greater than 100% of the acceptable dose are generally cause
for concern and would be considered ``unsafe'' within the meaning of
FFDCA section 408(b)(2)(B). For non-dietary (and combined dietary and
non-dietary) risk assessments of threshold effects, the toxicological
level of concern is typically not expressed as an RfD/PAD, but rather
in terms of an acceptable (or target) Margin of Exposure (MOE) between
human exposure and the PoD. The ``margin'' that is being referred to in
the term MOE is the ratio between the PoD and human exposure, which is
calculated by dividing human exposure into the PoD. An acceptable MOE
is generally considered to be a margin at least as high as the product
of all applicable safety factors for a pesticide. For example, when the
Agency retains the default uncertainty factors for dietary or aggregate
risk (a 10X interspecies uncertainty factor, a 10X intraspecies
uncertainty factor, and a 10X FQPA safety factor), the total
uncertainty factor (or level of concern) is 1,000, and any MOE above
1,000 represents exposures that are not of concern. Like RfD/PADs,
specific target MOEs are selected for exposures of different durations
and routes. For non-
[[Page 99200]]
dietary exposures, EPA typically examines short-term, intermediate-
term, and long-term exposures. Additionally, target MOEs may be
selected based on both the duration of exposure and the various routes
of non-dietary exposure--dermal, inhalation, and oral. Target MOEs for
a given pesticide can vary depending on the characteristics of the
studies relied upon in choosing the PoD for the various duration and
route scenarios.
In addition, in a DWLOC aggregate risk assessment, the calculated
DWLOC is compared to the EDWC. Where EPA has calculated a DWLOC, it can
determine whether drinking water exposures will result in aggregate
risks of concern by comparing estimated pesticide concentrations in
drinking water to the DWLOC. As noted above, an aggregate DWLOC
represents the amount of allowable safe residues of pesticide in
drinking water because it represents the room remaining in the risk cup
after accounting for the food and residential exposures. The DWLOC
provides an estimate of the allowable safe concentrations of pesticides
in drinking water for comparison to EDWCs. When the EDWC is less than
the DWLOC, there are no risk concerns for aggregate exposures because
the Agency can conclude that the contribution from drinking water when
aggregated with food and residential/non-occupational exposures will
not exceed save levels of exposure. Conversely, an EDWC at or exceeding
the DWLOC would indicate a risk of concern, as those exposures to
chlorpyrifos in drinking water, when aggregated with exposures from
food and residential exposures, would exceed safe levels of exposure.
(Ref. 41).
1. Dietary Risks From Food Exposures
As noted above, EPA's acute and steady-state dietary (food only)
exposure assessments for chlorpyrifos were highly refined and
incorporated monitoring data for almost all foods. The Agency assessed
food exposures based on all food uses of chlorpyrifos for which
tolerances have been established, including all uses registered at the
time of the 2020 HH DRA. It did not include potential exposure from
food handling establishment uses since the Agency did not identify any
actual usage under the registered food handling establishment uses.
Previous assessments of the food handling establishment uses had
indicated negligible residues. (Ref. 12 at 33-36 and 31 at 3).
Considering food exposures alone, the Agency did not identify risks
of concern for either acute or steady-state exposures. (Ref. 12 at 34-
36) Acute dietary (food only) risk estimates, which are based on risk
from a single exposure event in the 2020 HH DRA, were all below 100% of
the acute population adjusted dose for food (aPADfood) at
the 99.9th percentile of exposure and are not of concern. The
population with the highest risk estimate was females (13 to 49 years
old) at 3.2% aPADfood. Steady-state dietary (food only) risk
estimates, which are based on the potential risk from a 21-day exposure
duration using a 3-week rolling average (sliding by day) across the
year, were also all below 100% of the steady-state PAD for food
(ssPADfood) at the 99.9th percentile of exposure and are not
of concern. The population with the highest risk estimate was children
(1 to 2 years old) at 9.7% ssPADfood. Note: Because the
Agency has retained the 10X FQPA SF, as indicated in Unit VI.C.3., the
relevant risk estimates are those associated with the retention of the
10X FQPA SF. The risk estimates associated with a 1X FQPA SF were
provided solely to identify a range of risk estimates to characterize
the risk in the event that EPA identified reliable data to support
another FQPA SF that would be safe for infants and children, but no
such data has been identified.
Following the approval of the product and use cancellation
requests, the Agency has not conducted a separate quantitative
assessment of the anticipated risk from food exposures from the 11 food
uses remaining. Given that the cancellation actions will reduce
exposure from residues in food and the current assessment with all
currently registered food uses indicates there is no risk of concern
from exposure to residues on all food for which there are tolerances,
the Agency concludes that there will still be no risks of concern from
exposure to residues of chlorpyrifos on food after most of the food
uses are cancelled.
2. Non-Occupational, Non-Dietary (Residential) Risks
Because there are some uses of chlorpyrifos that may result in
residential exposures, EPA assessed risk from those uses. All
residential post-application risk estimates for the registered uses of
chlorpyrifos were below the Agency's level of concern. (Ref. 12 at 38)
The residential post-application LOC for children is 40, and the lowest
risk estimate for children (11 to less than 16 years old) was 1,200.
The residential post-application LOC for adults is 100, and the lowest
risk estimate is 1,000. Because the calculated MOEs are above the
Agency's level of concern, there are no risks of concern from
residential exposures.
3. Risks From Drinking Water
As noted above, the Agency aggregated exposures to chlorpyrifos
from food and residential exposures and calculated the DWLOC, i.e., the
amount of drinking water exposures that would be considered safe, based
on how much room was left in the risk cup after accounting for food and
residential/non-occupational exposures. The Agency calculated acute and
steady-state DWLOCs for infants (less than 1 year old); children (1 to
2 years old); youths (6 to 12 years old), and adults (females 13 to 49
years old), which would be protective of other subpopulations. The most
sensitive acute DWLOC was 23 ppb chlorpyrifos oxon, and the most
sensitive steady-state DWLOC was 4.0 ppb chlorpyrifos oxon.
As indicated above in Unit IV.B.2., the Agency estimated drinking
water contributions from the 11 food uses identified in Unit III. above
in its 2020 DWA for both acute and steady-state exposure durations.
Those estimates were based on limiting those uses to specific states
and were modeled based on usage data concerning application frequency
and application rates. These application rate and maximum number of
application-per-year restrictions vary by use site, as specified in the
2020 DWA. (Ref. 2) That document indicated that EDWCs for those food
uses with those specific limitations would be below the acute DWLOC of
23 ppb and the steady-state DWLOC of 4.0 ppb. The underlying assumption
of the 2020 DWA was that there would be no other food uses contributing
to drinking water exposures. As indicated in Unit III., all
chlorpyrifos registrants have submitted requests to cancel all other
food uses and to amend products for use on food consistent with the
restrictions identified in Unit III; EPA has completed approval of the
label amendments and expects to finalize the cancellations by the end
of 2024, prior to the time this rule is finalized. Under the terms of
those cancellation orders, use of chlorpyrifos will not be permitted on
food except on the 11 remaining uses in accordance with the new label
restrictions after June 30, 2025. As a result, EPA anticipates that use
of chlorpyrifos products with the more restrictive labeling will result
in drinking water exposures below the DWLOC.
4. Aggregate Exposure and Determination Concerning Safety
As noted above, in accordance with FFDCA section 408(b)(2), EPA
must,
[[Page 99201]]
when establishing or leaving in effect tolerances for residues of a
pesticide chemical, determine that the tolerances are safe. That is,
EPA must determine 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 all other exposures for
which there is reliable information.'' (21 U.S.C. 346a(b)(2)).
As discussed earlier in this Unit, exposures from food and
residential/non-occupational exposures, taken separately or together,
do not exceed EPA's levels of concern. The Agency determined that risks
from exposures to chlorpyrifos residues in food (from all food uses
registered at the time of the 2020 HHRA) comprised 3.2% of the aPAD for
females (13 to 49 years old) and 9.7% of the ssPAD for children (1 to 2
years old), the highest exposed subpopulations. Combining those
exposures with relevant residential exposures, which did not exceed the
Agency's levels of concern, the Agency calculated the levels of
drinking water concentrations that would be safe, i.e., the DWLOCs. The
lowest DWLOC for acute exposures (for infants) is 23 ppb, and the
lowest DWLOC for steady-state exposures (for infants) is 4.0 ppb;
therefore, any EDWCs of chlorpyrifos oxon exceeding 23 ppb in an acute
scenario or 4.0 ppb in a steady-state exposure scenario indicate that
aggregate exposures of chlorpyrifos would be unsafe.
The Agency's 2020 DWA demonstrates that the DWLOCs will not be
exceeded for the 11 uses as assessed in that document, i.e., where
those uses are limited to specific geographic areas and with
restrictions on application rates and frequency. Those restrictions are
described in Unit III. Because the registrants have, under FIFRA,
requested cancellation of all other food uses and have submitted label
amendments that reflect the necessary restrictions on the remaining
food uses for consistency with the assumptions in the 2020 DWA, EPA
considers the more limited exposure to be reasonably anticipated at
this time, unlike at the time of the 2021 Final Rule when no such
requests had been submitted. Use consistent with the amended labels
will result in drinking water exposures that are below the DWLOC, and
consequently, there is a reasonable certainty that no harm will result
from aggregate exposure (including food, drinking water, and
residential/non-occupational exposures) to chlorpyrifos. Therefore, EPA
concludes that the tolerances remaining in place will be safe.
V. Petition Response
As noted in Unit II.D., PANNA and NRDC submitted a petition to EPA
in September 2007, seeking revocation of all chlorpyrifos tolerances
and cancellation of all chlorpyrifos registrations (``2007 Petition'').
The 2007 Petition raised the following claims in support of that
request:
1. EPA has ignored genetic evidence of vulnerable populations.
2. EPA has needlessly delayed a decision regarding endocrine
disrupting effects.
3. EPA has ignored data regarding cancer risks.
4. EPA's 2006 OP CRA misrepresented risks and failed to apply the
10X FQPA Safety Factor.
5. EPA has over-relied on registrant data.
6. EPA has failed to properly address the exporting hazard in
foreign countries from chlorpyrifos.
7. EPA has failed to quantitatively incorporate data demonstrating
long-lasting effects from early life exposure to chlorpyrifos in
children.
8. EPA has disregarded data demonstrating that there is no evidence
of a safe level of exposure during pre-birth and early life stages.
9. EPA has failed to cite or quantitatively incorporate studies and
clinical reports suggesting potential adverse effects below 10%
cholinesterase inhibition.
10. EPA has failed to incorporate inhalation routes of exposure.
In a response dated July 16, 2012, EPA explained that all but one
of the issues raised in the 2007 Petition relate to EPA's establishment
of the chlorpyrifos tolerances under the FFDCA that would be addressed
in either a rule or an order issued under the FFDCA. (Ref. 42) The one
issue that was not related to the safety of the tolerances was claim 6,
which EPA denied in that July 16, 2012, response. EPA expressly noted
that its denial of claim 6 was a final agency action subject to
judicial review under section 16 of FIFRA; that denial was never
challenged.
The only claims remaining in the 2007 Petition, therefore, are
claims related to the safety of the chlorpyrifos tolerances that must
be addressed under the FFDCA. Because of the integration of the safety
standard into the FIFRA registration standard, if EPA were to determine
that the tolerances were unsafe, then the corresponding food uses would
not meet the FIFRA standard for registration and must be cancelled. If,
however, EPA were to determine that the 2007 Petition does not provide
a basis for determining that the tolerances associated with the 11
remaining food uses are unsafe, as EPA is proposing to do in this
document, there would be no separate basis in the 2007 Petition for a
cancellation action under FIFRA. Section 408(h)(5) prohibits the review
of issues under other statutes, for which review is obtainable under
the FFDCA. 21 U.S.C. 346a(h)(5). Accordingly, EPA intended, as
indicated in its July 2012 response, and intends currently to treat the
final rule of this rulemaking as its final response to the remaining
claims in the 2007 Petition.
Regarding the remaining claims, which must be reviewed under the
FFDCA, EPA denied the rest of the claims in the 2017 Denial Order and
denied the objections to that order in the 2019 Denial Order. (Ref. 10
and 43) After the 2017 and 2019 Denial Orders were vacated by the Ninth
Circuit in 2021, EPA granted the 2007 Petition as part of the 2021
Final Rule, as directed by the Ninth Circuit, but that 2021 Final Rule
(and petition response) was subsequently vacated by the Eighth Circuit
in 2023.
As noted above, however, EPA is taking action in this rulemaking to
revoke most tolerances, which is consistent, in part, with the 2007
Petition's request. Based on the available data, use of chlorpyrifos
has been decreasing (also noted in section IV.B.4 of this rule).
Cancelling all food uses but the 11 mentioned in Unit III. above--along
with geographic limitations and additional application restrictions--
will contribute to the decrease of chlorpyrifos applied in the United
States compared to historical usage. In addition, to address concerns
about whether the rest of the tolerances should be revoked as requested
by the 2007 Petition, EPA has provided a safety determination in Unit
IV. above. To the extent the Petition's request to revoke tolerances is
not fully addressed above, EPA is clarifying its responses to the
specific claims in this Unit.
EPA provided responses to the specific claims 1-5 and 10 in the
2017 Denial Order. EPA's position on those issues has not changed, and
thus EPA is incorporating those responses into this document by
reference. Those responses can be found in Unit V.1-5 and 10 of the
2017 Petition Denial. See 82 FR at 16585-91.
EPA has grouped claims 7-9 together because they fundamentally all
raise the same issue: Whether the potential exists for chlorpyrifos to
cause neurodevelopmental effects in infants and children from exposures
(either to mothers during pregnancy or directly to
[[Page 99202]]
infants and children) that are lower than those resulting in 10%
cholinesterase inhibition--the basis for EPA's long-standing point of
departure in regulating chlorpyrifos and other OPs.
The petitioners assert that human epidemiology and rodent
developmental neurotoxicity data suggest that pre-natal and early life
exposure to chlorpyrifos can result in long-lasting, possibly permanent
damage to the nervous system and that these effects are likely
occurring at exposure levels below 10% cholinesterase inhibition, EPA's
existing regulatory standard for chlorpyrifos and other OPs. They
assert that EPA has therefore used the wrong endpoint as a basis for
regulation and that, taking into account the full spectrum of toxicity,
chlorpyrifos does not meet the FFDCA safety standard (and thus does not
meet the FIFRA standard for registration, which integrates the FFDCA
safety standard).
EPA initiated a science evaluation of the potential effects on
neurodevelopment in 2007 following the receipt of the 2007 Petition.
EPA has three times presented approaches and proposals to the FIFRA SAP
for evaluating epidemiologic, laboratory animal, and mechanistic data
exploring the possible connection between in utero and early childhood
exposure to chlorpyrifos and adverse neurodevelopmental effects. The
FIFRA SAP reports have rendered numerous recommendations for additional
study and sometimes conflicting advice for how EPA should consider (or
not consider) the epidemiology data in conducting EPA's registration
review human health risk assessment for chlorpyrifos. For over two
decades, EPA has evaluated the scientific evidence surrounding the
different health effects associated with chlorpyrifos. The Agency's
position on the strengths and weaknesses of the available
epidemiological, laboratory animal, and mechanistic data as laid out in
the 2020 HH DRA is discussed in Unit IV.A.2.b above.
As noted in that section and in Unit IV.A.3., EPA concludes that
the available epidemiological data does not provide a sufficient basis
for calculating a PoD nor does it support a conclusion that PoDs based
on the 10% AChE inhibition are not protective. Nevertheless, as
discussed in Unit IV.A.3.c., EPA has retained the 10X FQPA SF to
account for the uncertainties around the dose-response level for
neurodevelopmental effects for the purpose of this rule.
Through this proposal, EPA is proposing to take action to revoke
most chlorpyrifos tolerances as requested in the 2007 Petition but is
not proposing to revoke tolerances associated with the remaining
registered uses because the Agency's analysis in the 2020 HH DRA and
the 2020 DWA support a conclusion that those tolerances are safe. The
voluntary cancellations will effectuate a reduction in exposures, and
because exposures will be reduced, the underlying assessment, even with
the retention of the default 10X FQPA SF, supports the retention of the
remaining tolerances.
EPA is proposing that the claims in the 2007 Petition do not
provide a basis for concluding that the tolerances not being revoked
are unsafe.
VI. Request for Public Comment
The Agency is requesting comments on this proposal.
During the lengthy pendency of the 2007 Petition to revoke
tolerances and the registration review process for chlorpyrifos, the
public has had numerous opportunities to comment on EPA's scientific
conclusions, risk assessments, regulatory proposals, and rules.
Hundreds of thousands of comments have been submitted, and those
comments have informed EPA's subsequent assessments and regulatory
decision making.
As this is a proposed rule, EPA is providing an opportunity to
comment on issues related to this proposal, and EPA will consider
significant comments in the final rule. Comments on this particular
proposal must be submitted at this time, even if that person has
submitted comments at other times during the history of chlorpyrifos
regulatory actions.
VII. Other Administrative Considerations
A. Tolerance Expiration Date
EPA is proposing to set an expiration date for the chlorpyrifos
tolerances being revoked so that those tolerances will expire on July
1, 2025. This date would align with the existing stocks provisions for
the related cancellation actions, which allow use of existing stocks of
some cancelled chlorpyrifos products on food until June 30, 2025. This
approach is also intended to satisfy the U.S. commitments under the SPS
Agreement, requiring Members to provide a ``reasonable interval''
between the publication of a regulation subject to the Agreement and
its entry into force to allow time for producers in exporting Member
countries to adapt to the new requirement.
Any commodities treated with chlorpyrifos that are in the channels
of trade and impacted by the tolerance revocations shall be subject to
FFDCA section 408(1)(5). That section provides that any residues of the
subject pesticide in or on such food shall not render the food
adulterated so long as it is shown to the satisfaction of the Food and
Drug Administration that:
1. The residue is present as the result of an application or use of
the pesticide at a time and in a manner that was lawful under FIFRA,
and
2. The residue does not exceed the level that was authorized at the
time of the application or use to be present on the food under a
tolerance or exemption from tolerance. Evidence to show that food was
lawfully treated may include records that verify the dates when the
pesticide was applied to such food.
The tolerance revocations in this proposed rule are not
discriminatory and are designed to ensure that both domestically
produced and imported foods meet the food safety standard established
by the FFDCA. The same food safety standards apply to domestically
produced and imported foods.
B. Severability
This proposed rule includes two distinct actions concerning
chlorpyrifos tolerances. Specifically, the Agency is proposing: (1) to
revoke all tolerances associated with use cancellations as those
tolerances are no longer needed and (2) that the tolerances not being
revoked are safe. The Agency intends that these two actions be
severable from each other, although for purposes of expediency and to
fully address the pending 2007 Petition, EPA is proposing to include
all parts in one rulemaking. (21 U.S.C. 346a(l)(1)). However, EPA
retains the discretion to take each of these actions separately, with
each implementing a portion or portions of this proposed rule.
The revocation of tolerances that are no longer needed is an almost
entirely ministerial action. Because those uses of chlorpyrifos on
these commodities will no longer be registered in the United States,
the corresponding tolerances are considered unnecessary. The Agency's
typical process is to automatically remove tolerances from the
regulations that are no longer necessary. The only element of agency
discretion involved in revocation of most tolerances would arise from a
hypothetical request that EPA retain certain tolerances for purposes of
importing food treated with chlorpyrifos. The proposal to revoke all
tolerances except for those on the 11 specified crops depends neither
on the Agency making a safety finding for the remaining tolerances nor
on the Agency's response to the 2007 Petition.
[[Page 99203]]
Even if safety of the tolerances not being revoked is challenged, the
revocation of unnecessary tolerances would not be affected and would
stand on its own right; EPA could re-evaluate the safety of the
remaining tolerances and either provide additional justification for
its safety determination or take other action--if needed--to address
the safety of chlorpyrifos tolerances. The tolerances proposed for
revocation in this document would remain revoked in such circumstances.
This discussion of separate actions proposed in this document is
not intended to be exhaustive and should not be viewed as an intention
by EPA to consider other actions or determinations proposed herein as
non-severable from other parts of the proposed rule.
VIII. Statutory and Executive Order Reviews
In this proposed rule, EPA is proposing to revoke specific
tolerances established under FFDCA section 408. The Office of
Management and Budget (OMB) has exempted this type of action (e.g.,
tolerance revocation for which extraordinary circumstances do not
exist) from review under Executive Order 12866, entitled ``Regulatory
Planning and Review'' (58 FR 51735, October 4, 1993). These revocations
are not expected to present extraordinary circumstances because the
registrants have requested to voluntarily cancel uses associated with
these tolerances, which means that the tolerances will no longer be
needed to cover residues of chlorpyrifos in or on those food
commodities. Because this proposed rule has been exempted from review
under Executive Order 12866, this proposed rule is not subject to
Executive Order 13211, entitled ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR
28355, May 22, 2001).
This proposed rule does not contain any information collections
subject to OMB approval under the Paperwork Reduction Act (PRA) (44
U.S.C. 3501 et seq.) or impose any enforceable duty or contain any
unfunded mandate as described under Title II of the Unfunded Mandates
Reform Act (UMRA) (2 U.S.C. 1501 et seq.). Nor does it require any
special considerations as required by Executive Order 12898, entitled
``Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations'' (59 FR 7629, February 16,
1994); or OMB review or any other Agency action under Executive Order
13045, entitled ``Protection of Children from Environmental Health
Risks and Safety Risks'' (62 FR 19885, April 23, 1997). However, EPA
considered the best available science in order to protect children
against environmental health risks and this proposed rule is consistent
with EPA's 2021 Policy on Children's Health (Oct. 5, 2021). (Ref. 43).
This proposed rule does not involve any technical standards that
would require Agency consideration of voluntary consensus standards
pursuant to section 12(d) of the National Technology Transfer and
Advancement Act (NTTAA) (15 U.S.C. 272 note). In addition, the Agency
has determined that this proposed rule will not have a substantial
direct effect on States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government, as specified
in Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999). This proposed rule directly regulates growers, food
processors, food handlers, and food retailers, not states, including a
state's ability to register pesticide products. This proposed rule does
not alter the relationships or distribution of power and
responsibilities established by Congress in the preemption provisions
of FFDCA section 408(n)(4). For these same reasons, the Agency has
determined that this proposed rule does not have any ``tribal
implications'' as described in Executive Order 13175, entitled
``Consultation and Coordination with Indian Tribal Governments'' (65 FR
67249, November 9, 2000).
In addition, pursuant to section 605(b) of the Regulatory
Flexibility Act (RFA) (5 U.S.C. 601 et seq.), the Agency hereby
certifies that the revocation of these tolerances in response to the
cancellation of associated food uses will not have a significant impact
on a substantial number of small entities. The certification presented
above is based on the following rationale. In the case of domestically
grown food, the tolerance revocations contained in this notice, as is
generally the case, will have no economic impact. The associated
pesticide registered uses are in the process of being canceled at this
time, as requested by the registrants. By the time this rule is
finalized, EPA intends to have approved all requested cancellations,
and use will only be permitted on food consistent with the existing
stocks provisions of those orders. Pursuant to the cancellation orders,
U.S. growers will be prohibited from using chlorpyrifos on the foods
for which this rule proposes revoking tolerances after June 30, 2025.
Accordingly, revoking the tolerances themselves will have no effect on
food grown in the United States. As for food grown in the United
States, it will not be considered adulterated if it was treated in a
way that complied with the tolerance in effect at the time of treatment
and the use is consistent with the applicable cancellation order. The
revocation of a pesticide tolerance generally has a greater potential
to affect foreign-grown food, since the uses of the pesticide
prohibited in the United States may still be lawful in other countries.
If foreign growers use the pesticide after the tolerances are revoked,
the food they grow will be considered adulterated and cannot be
imported.
IX. References
EPA has established an official record for this rulemaking. The
official record includes all information considered by EPA in
developing this proposed rule. This official record includes all
information physically located in docket ID number EPA-HQ-OPP-2024-
0431, any documents identified in this proposal, and documents
referenced in documents in the docket. The public version of the
official record does not include any information claimed as CBI.
1. U.S. EPA (2020). Chlorpyrifos Proposed Interim Registration
Review Decision. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0971.
2. U.S. EPA (2020). Chlorpyrifos Updated Drinking Water Assessment
for Registration Review. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0941.
3. U.S. EPA (2022). Cancellation Order for Certain Chlorpyrifos
Registrations. Available at: https://www.federalregister.gov/documents/2022/08/31/2022-18838/cancellation-order-for-certain-chlorpyrifos-registrations.
4. U.S. EPA (2023). Final Cancellation Order for Certain
Chlorpyrifos Registrations and Uses. Available at: https://www.federalregister.gov/documents/2023/11/06/2023-24462/final-cancellation-order-for-certain-chlorpyrifos-registrations-and-uses.
5. U.S. EPA (2023). Cancellation Order for Certain Chlorpyrifos
Registrations and Uses. Available at: https://www.federalregister.gov/documents/2023/05/04/2023-09396/cancellation-order-for-certain-chlorpyrifos-registrations-and-uses.
6. U.S. EPA (2023). Final Cancellation Order for Certain
Chlorpyrifos Registrations and Uses. Available at: https://www.federalregister.gov/documents/2023/11/06/2023-24462/final-cancellation-order-for-certain-chlorpyrifos-registrations-and-uses.
7. U.S. EPA (2024). Final Cancellation Order for Certain
Chlorpyrifos Registrations
[[Page 99204]]
and Uses. Available at: https://www.federalregister.gov/documents/2024/06/24/2024-13779/final-cancellation-order-for-cancelling-certain-pesticide-registrations-and-uses.
8. U.S. EPA (2024) Chlorpyrifos; Final Cancellation Order for
Certain Pesticide Registrations and Amendment of Certain Pesticide
Registrations to Terminate Certain Uses. Available at: https://www.federalregister.gov/documents/2024/08/07/2024-17453/chlorpyrifos-final-cancellation-order-for-certain-pesticide-registrations-and-amendment-of-certain.
9. U.S. EPA (2016). Chlorpyrifos: Revised Human Health Risk
Assessment for Registration Review (November 3, 2016). Available at:
https://www.regulations.gov/document/EPA-HQ-OPP-2015-0653-0454.
10. U.S. EPA (2017) Chlorpyrifos; Order Denying PANNA and NRDC's
Petition to Revoke Tolerances. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2007-1005-0100.
11. U.S. EPA (2023) Pesticide Tolerance; Exemptions, Petitions,
Revocations, etc.: Implementing Registration Review Decisions for
Certain Pesticides; Aluminum tris (O-ethylphosphonate), Carbon
disulfide, et al. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2017-0128-0005.
12. U.S. EPA (2020) Chlorpyrifos: Third Revised Human Health Risk
Assessment for Registration Review. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0944.
13. A User's Guide to Available EPA Information on Assessing
Exposure to Pesticides in Food (June 21, 2000). Available at:
https://www.doh.wa.gov/Portals/1/Documents/4000/PASW_exposurefood.pdf.
14. U.S. EPA (2002) Determination of the Appropriate FQPA Safety
Factor(s) in Tolerance Assessment. Available at: https://www.epa.gov/sites/default/files/2015-07/documents/determ.pdf.
15. U.S. EPA (2000). Chlorpyrifos Human Health Risk Assessment.
Available at: https://archive.epa.gov/scipoly/sap/meetings/web/pdf/hed_ra.pdf.
16. U.S. EPA (2011). Chlorpyrifos: Preliminary Human Health Risk
Assessment for Registration Review. Available in docket number EPA-
HQ-OPP-2008-0850, https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0025.
17. U.S. EPA (2016). Scientific Advisory Panel for Chlorpyrifos:
Analysis of Biomonitoring Data. Available at: https://www.epa.gov/sites/default/files/2016-07/documents/chlorpyrifos_sap_april_2016_final_minutes.pdf.
18. U.S. EPA (2016). Summary Reviews for Additional Epidemiological
Literature Studies from Prospective Birth Cohort Studies. Available
in docket number EPA-HQ-OPP-2015-0653 at https://www.regulations.gov/document/EPA-HQ-OPP-2015-0653-0438.
19. U.S. EPA (2020). The Use of New Approach Methodologies (NAMs) to
Derive Extrapolation Factors and Evaluate Developmental
Neurotoxicity for Human Health Risk Assessment. Available in docket
number EPA-HQ-OPP-2020-0263 at https://www.regulations.gov/document/EPA-HQ-OPP-2020-0263-0033.
20. FIFRA Scientific Advisory Panel (2012). ``Scientific Issues
Associated with Chlorpyrifos''. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2012-0040-0029.
21. U.S. EPA (2006). Revised Organophosphorous Pesticide Cumulative
Risk Assessment. Available at https://downloads.regulations.gov/EPA-HQ-OPP-2006-0618-0002/content.pdf.
22. U.S. EPA (2012). Standard Operating Procedures for Residential
Pesticide Exposure Assessment https://www.epa.gov/sites/default/files/2015-08/documents/usepa-opp-hed_residential_sops_oct2012.pdf.
23. FIFRA Scientific Advisory Panel (2002). ``Organophosphate
Pesticides: Preliminary OP Cumulative Risk Assessment.'' Information
on how to obtain the meeting report is available at https://www.epa.gov/sap/fifra-scientific-advisory-panel-meetings.
24. EPA's Exposure Factors Handbook. Available at: https://www.epa.gov/expobox/about-exposure-factors-handbook.
25. U.S. EPA (2014). Guidance for Applying Quantitative Data to
Develop Data-Derived Extrapolation Factors for Interspecies and
Intraspecies Extrapolation. Available at: https://www.epa.gov/sites/default/files/2015-01/documents/ddef-final.pdf.
26. U.S. EPA (2014). Chlorpyrifos: Revised Human Health Risk
Assessment for Registration Review. Available in docket number EPA-
HQ-OPP-2008-0850, https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0195.
27. U.S. EPA (2016). Office of Pesticide Programs' Framework for
Incorporating Human Epidemiologic & Incident Data in Risk
Assessments for Pesticides. (2016) Available at: https://www3.epa.gov/pesticides/EPA-HQ-OPP-2008-0316-DRAFT-0075.pdf.
28. A User's Guide to Available EPA Information on Assessing
Exposure to Pesticides in Food (June 21, 2000). Available at:
https://www.doh.wa.gov/Portals/1/Documents/4000/PASW_exposurefood.pdf.
29. U.S. EPA (2000). Choosing a Percentile of Acute Dietary Exposure
as a Threshold of Regulatory Concern. Available at: https://www.epa.gov/sites/production/files/2015-07/documents/trac2b054_0.pdf.
30. U.S. EPA (2014). Chlorpyrifos Acute and Steady Dietary (Food
Only) Exposure Analysis to Support Registration Review. Available
at: https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0197.
31. U.S. EPA (2020). Framework for Conducting Pesticide Drinking
Water Assessments for Surface Water. Environmental Fate and Effects
Division. Office of Pesticide Programs. Office of Chemical Safety
and Pollution Prevention. U.S. Environmental Protection Agency.
Available at: https://www.epa.gov/sites/default/files/2020-09/documents/framework-conducting-pesticide-dw-sw.pdf.
32. FIFRA Scientific Advisory Panel (2019) ``Approaches for
Quantitative Use of Surface Water Monitoring Data in Pesticide
Drinking Water Assessments.'' Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2019-0417-0019.
33. U.S. EPA (2001). General Principles for Performing Aggregate
Exposure and Risk Assessments. Available at: https://www.epa.gov/sites/default/files/2015-07/documents/aggregate.pdf.
34. United States Geological Survey (USGS) Water Resources of the
United States https://water.usgs.gov/GIS/huc.html.
35. U.S. EPA (2020). Appendix B. Case Study for Integrating a
Distributional Approach to Using Percent Crop Area (PCA) and Percent
Crop Treated (PCT) into Drinking Water Assessment. Available at:
https://www.regulations.gov/document/EPA-HQ-OPP-2020-0279-0002.
36. U.S. EPA (2016). Chlorpyrifos Refined Drinking Water Assessment
for Registration Review. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2015-0653-0437.
37. U.S. EPA (2014). Chlorpyrifos Updated Drinking Water Assessment
for Registration Review. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2008-0850-0198.
38. U.S. EPA (2015). Proposed Rule: Tolerance Revocations:
Chlorpyrifos. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2015-0653-0001.
39. U.S. EPA (2019). Documents on PCA/PCT and New Scenario Methods
for Estimating Pesticide Concentration in Drinking Water. Available
at https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks/documents-pcapct-and-new-scenario-methods.
40. U.S. EPA (2020). Pesticide Drinking Water Assessment
Improvements. Available at https://www.regulations.gov/docket/EPA-HQ-OPP-2020-0279/document.
41. U.S. EPA (2011). Finalization of Guidance on Incorporation of
Water Treatment Effects on Pesticide Removal and Transformations in
Drinking Water Exposure Assessments. Available at: https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks/finalization-guidance-incorporation-water-treatment.
42. U.S. EPA (2012) EPA's Partial Response to Chlorpyrifos Petition
by NRDC & PANNA. Available at: https://www.regulations.gov/document/EPA-HQ-OPP-2007-1005-0095.
43. U.S. EPA (2019) Chlorpyrifos; Final Order Denying Objections to
March 2017 Petition Denial Order. Available at https://www.regulations.gov/document/EPA-HQ-OPP-2007-1005-0527.
[[Page 99205]]
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: November 27, 2024.
Edward Messina,
Director, Office of Pesticide Programs.
Therefore, for the reasons stated in the preamble the Environmental
Protection Agency proposes to amend 40 CFR part 180 as follows:
PART 180--TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES
IN FOOD
0
1. The authority citation for part 180 continues to read as follows:
Authority: 21 U.S.C. 321(q), 346a and 371.
0
2. Revise Sec. 180.342 to read as follows:
Sec. 180.342 Chlorpyrifos; tolerances for residues.
(a) General. (1) Tolerances are established for residues of the
pesticide chlorpyrifos per se (O,O-diethyl-O-(3,5,6-trichloro-2-
pyridyl) phosphorothioate) in or on the following food commodities:
Table 1 to Paragraph (a)(1)
------------------------------------------------------------------------
Tolerance
Commodity Parts per million expiration date
------------------------------------------------------------------------
Alfalfa, forage................. 3.0 None
Alfalfa, hay.................... 13 None
Almond.......................... 0.2 7/1/2025
Almond, hulls................... 12 7/1/2025
Apple........................... 0.01 None
Apple, wet pomace............... 0.02 None
Banana.......................... 0.1 7/1/2025
Beet, sugar, dried pulp......... 5.0 None
Beet, sugar, molasses........... 15 None
Beet, sugar, roots.............. 1.0 None
Beet, sugar, tops............... 8.0 None
Cattle, fat..................... 0.3 None
Cattle, meat.................... 0.05 None
Cattle, meat byproducts......... 0.05 None
Cherry, sweet................... 1.0 7/1/2025
Cherry, tart.................... 1.0 None
Citrus, dried pulp.............. 5.0 None
Citrus, oil..................... 20 None
Corn, field, forage............. 8.0 7/1/2025
Corn, field, grain.............. 0.05 7/1/2025
Corn, field, refined oil........ 0.25 7/1/2025
Corn, field, stover............. 8.0 7/1/2025
Corn, sweet, forage............. 8.0 7/1/2025
Corn, sweet, kernel plus cob 0.05 7/1/2025
with husk removed..............
Corn, sweet, stover............. 8.0 7/1/2025
Cotton, undelinted seed......... 0.2 None
Cranberry....................... 1.0 7/1/2025
Cucumber........................ 0.05 7/1/2025
Egg............................. 0.01 7/1/2025
Fig............................. 0.01 7/1/2025
Fruit, citrus, group 10......... 1.0 None
Food commodities (other than 0.1 7/1/2025
those already covered by a
higher tolerance as a result of
use on growing crops) in food
service establishments where
food and food products are
prepared and served, as a
result of the application of
chlorpyrifos in
microencapsulated form.........
Goat, fat....................... 0.2 None
Goat, meat...................... 0.05 None
Goat, meat byproducts........... 0.05 None
Hazelnut........................ 0.2 7/1/2025
Hog, fat........................ 0.2 None
Hog, meat....................... 0.05 None
Hog, meat byproducts............ 0.05 None
Horse, fat...................... 0.25 None
Horse, meat..................... 0.25 None
Horse, meat byproducts.......... 0.25 None
Kiwifruit....................... 2.0 7/1/2025
Milk, fat (Reflecting 0.01 ppm 0.25 None
in whole milk).................
Nectarine....................... 0.05 7/1/2025
Onion, bulb..................... 0.5 7/1/2025
Peach........................... 0.05 None
Peanut.......................... 0.2 7/1/2025
Peanut, refined oil............. 0.2 7/1/2025
Pear............................ 0.05 7/1/2025
Pecan........................... 0.2 7/1/2025
Pepper.......................... 1.0 7/1/2025
Peppermint, tops................ 0.8 7/1/2025
Peppermint, oil................. 8.0 7/1/2025
[[Page 99206]]
Plum, prune, fresh.............. 0.05 7/1/2025
Poultry, fat.................... 0.1 None
Poultry, meat................... 0.1 None
Poultry, meat by products....... 0.1 None
Pumpkin......................... 0.05 7/1/2025
Radish.......................... 2.0 7/1/2025
Rutabaga........................ 0.5 7/1/2025
Sheep, fat...................... 0.2 None
Sheep, meat..................... 0.05 None
Sheep, meat byproducts.......... 0.05 None
Spearmint, tops................. 0.8 7/1/2025
Spearmint, oil.................. 8.0 7/1/2025
Sorghum, grain, forage.......... 0.5 7/1/2025
Sorghum, grain, grain........... 0.5 7/1/2025
Sorghum, grain, stover.......... 2.0 7/1/2025
Soybean, seed................... 0.3 None
Strawberry...................... 0.2 None
Sunflower, seed................. 0.1 7/1/2025
Sweet potato, roots............. 0.05 7/1/2025
Turnip, roots................... 1.0 7/1/2025
Turnip, tops.................... 0.3 7/1/2025
Vegetable, brassica, leafy, 1.0 7/1/2025
group 5........................
Vegetable, legume, group 6, 0.05 7/1/2025
except soybean.................
Walnut.......................... 0.2 7/1/2025
Wheat, forage................... 3.0 None
Wheat, grain.................... 0.5 None
Wheat, straw.................... 6.0 None
------------------------------------------------------------------------
(2) Chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl)
phosphorothioate] may be safely used up until and including June 30,
2025 in accordance with the following prescribed conditions. On and
after July 1, 2025, chlorpyrifos may not be used as described below:
(i) Application shall be limited solely to spot and/or crack and
crevice treatment in food handling establishments where food and food
products are held, processed, prepared or served. Contamination of food
or food contact surfaces shall be avoided. Food must be removed or
covered during treatment.
(ii) Spray concentration for spot treatment shall be limited to a
maximum of 0.5 percent of the active ingredient by weight. A course,
low-pressure spray shall be used to avoid atomization or splashing of
the spray.
(iii) Paint-on application for spot treatment shall be limited to a
maximum of 2 percent of the active ingredient by weight.
(iv) Crack and crevice treatment shall be limited to a maximum of 2
percent of the active ingredient by weight. Equipment capable of
delivering a pin-stream of insecticide shall be used.
(v) Application via adhesive strips shall contain a maximum of 10%
by weight of the controlled-release product in food-handling
establishments where food and food products are held, processed,
prepared, or served. A maximum of 36 strips (or 5.15 grams of
chlorpyrifos) is to be used per 100 square feet of floor space. The
strips are not to be placed in exposed areas where direct contact with
food, utensils, and food-contact surfaces would be likely to occur.
(vi) To assure safe use of the insecticide, its label and labeling
shall conform to that registered by the U.S. Environmental Protection
Agency, and it shall be used in accordance with such label and
labeling.
(3) A tolerance of 0.1 part per million is established for residues
of chlorpyrifos, per se, in or on food commodities (other than those
already covered by a higher tolerance as a result of use on growing
crops) in food service establishments where food and food products are
prepared and served, as a result of the application of chlorpyrifos in
microencapsulated form. This tolerance expires on July 1, 2025.
(i) Application of a microencapsulated product shall be limited
solely to spot and/or crack and crevice treatment in food handling
establishments where food and food products are prepared and served.
All treatments shall be applied in such a manner as to avoid
contamination of food or food contact surfaces.
(ii) Spray concentrations shall be limited to a maximum of 0.5
percent of the active ingredient by weight.
(iii) For crack and crevice treatment, equipment capable of
delivering a pin stream of spray directly into cracks and crevices or
capable of applying small amounts of insecticide into cracks and
crevices shall be used.
(iv) For spot treatment, an individual spot shall not exceed 2
square feet.
(v) To assure safe use of the insecticide, its label and labeling
shall conform to that registered by the U.S. Environmental Protection
Agency, and it shall be used in accordance with such label and
labeling.
(b) [Reserved]
(c) Tolerances with regional registrations. Tolerances with
regional registration, as defined in 180.1(l), are established for
residues of the pesticide chlorpyrifos per se (O,O-diethyl- O-(3,5,6-
trichloro-2-pyridyl) phosphorothioate) in or on the following food
commodities:
[[Page 99207]]
Table 2 to Paragraph (c)
------------------------------------------------------------------------
Parts per Tolerance
Commodity million expiration date
------------------------------------------------------------------------
Asparagus........................... 5.0 None
Grape............................... 0.01 7/1/2025
------------------------------------------------------------------------
(d) [Reserved]
[FR Doc. 2024-28332 Filed 12-9-24; 8:45 am]
BILLING CODE 6560-50-P