Significant New Alternatives Policy Program 
Refrigeration and Air Conditioning Sector
Risk Screen on Substitutes for CFC-11 and HCFC-123 in Centrifugal Chillers
  Substitute: Trans-1-chloro-3,3,3-trifluoropro-1-ene (Solstice(TM) 1233zd(E))
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This risk screen does not contain Clean Air Act (CAA) Confidential Business Information (CBI) and, therefore, can be disclosed to the public.
1. 	INTRODUCTION
Ozone-depleting substances (ODS) are being phased out of production in response to a series of diplomatic and legislative efforts that have taken place over the past two decades, including the Montreal Protocol and the Clean Air Act Amendments of 1990 (CAAA).  The U.S. Environmental Protection Agency (EPA), as authorized by Section 612 of the CAAA, administers the Significant New Alternatives Policy (SNAP) Program, which identifies acceptable and unacceptable substitutes for ODS in specific end-uses based on assessment of their health and environmental impacts.  
EPA's decision on the acceptability of a substitute is based on the findings of a screening assessment of potential human health and environmental risks posed by the substitute in specific applications.  EPA has already screened a large number of substitutes in many end-uses within all of the major ODS-using sectors, including refrigeration and air conditioning, solvent cleaning, foam blowing, aerosols, fire suppression, adhesives, coatings and inks, and sterilization. The results of these risk screens are presented in a series of Background Documents that are available in EPA's docket.
The purpose of this risk screen is to supplement EPA's Background Document on the refrigeration and air conditioning sector (EPA 1994) (hereinafter referred to as the Background Document). This risk screen evaluates the potential use of trans-1-chloro-3,3,3-trifluoropro-1-ene (also know as (E) 1-chloro-3,3,3-trifluoroprop-1-ene and hereinafter referred to as Solstice[TM] 1233zd(E)) as a substitute for CFC-11 and HCFC-123 in low-pressure centrifugal chillers. Table 1 presents information on the proposed substitute. 
                Table 1. Composition of Solstice[TM] 1233zd(E)
                                  Constituent
                               Chemical Formula
                                  CAS Number
                               Percent of Total
                                (by weight)[a]
                   trans-1-chloro-3,3,3-trifluoroprop-1-ene
                                   C3H2ClF3
                                  102687-65-0
                                    >99%
                 Potential Impurities (maximum concentration)
                                       

The potential risks associated with use of substitutes in chillers have been examined at length in the Background Document.  The reader is referred to this reference for a detailed discussion of the methodologies used to conduct this risk screen.  This risk screen addresses flammability risk, and an occupational exposure assessment was performed to ensure that manufacture, installation, servicing, and disposal of the proposed substitute in the centrifugal chiller end-use does not pose unacceptable risk to workers.  Lastly, general population exposure modeling was performed to ensure that the proposed substitute would not pose an unacceptable risk to the population at large.  
Section 2 of this report summarizes the results of the risk screen for the proposed substitute listed in Table 1.  The remainder of the report is organized into the following sections:

         * Section 3: Atmospheric Assessment
         * Section 4: Flammability Assessment
         * Section 5: Potential Health Effects
         * Section 6: Occupational Exposure Assessment
         * Section 7: General Population Exposure Assessment
         * Section 8: Volatile Organic Compound Assessment
         * Section 9: References
2.	 SUMMARY OF RESULTS						
Solstice[TM] 1233zd(E) is recommended for SNAP approval for the centrifugal chiller end-use.  EPA's risk screen indicates that the use of the proposed substitute will be less harmful to the atmosphere than the continued use of CFC-11 and HCFC-123.   Given that appropriate safety and personal protective equipment (PPE) (OSHA Category C or higher)  and engineering controls (e.g., exhaust ventilation, vapor-in-air detection systems) will be used during installation, maintenance, and disposal activities, no significant toxicity risks to workers or the general population are expected.  In addition, based on the characteristics of the proposed substitute and the proper precautions listed in the MSDS for Solstice[TM] 1233zd(E), the proposed substitute is not expected to present a significant flammability concern during manufacture or end-use (see Section 4). 
3. 	ATMOSPHERIC ASSESSMENT
This section presents an assessment of the potential risks to atmospheric integrity posed by the use of Solstice[TM] 1233zd(E) in the refrigeration and air-conditioning sector.  The ozone depletion potential (ODP), global warming potential (GWP), and atmospheric lifetime (ALT) of the proposed substitute are presented in Table 2. As compared to CFC-11 and HCFC-123, Solstice[TM] 1233zd(E) is substantially less harmful to the ozone layer, has less climate impact, and a shorter atmospheric lifetime. In addition, Solstice[TM] 1233zd(E) also has lower climate impact and a shorter atmospheric lifetime than those predicted for other substitutes examined in the Background Document. Solstice[TM] 1233zd(E) does however, also have a non-zero ODP, but at 0.00024, this value is very small. A recent report by Wang et. al. (2011) modeled the potential of Solstice[TM] 1233zd(E) to affect the amount of ozone in the global atmosphere. This report found that the release of all Solstice[TM] 1233zd(E), assuming it were substituted for all compounds it might replace, would have a statistically zero impact on global atmospheric ozone (less than 0.01% change in total column ozone). Thus, EPA believes that use of Solstice[TM] 1233zd(E) would result in substantially less harm to the climate and ozone layer than the continued use of ODS. 

Table 2. Atmospheric Impacts of Solstice[TM] 1233zd(E) Compared to CFC-11 and HCFC-123
                                  Refrigerant
                                      ODP
                                      GWP
                                     ALT 
                            Solstice[TM] 1233zd(E)
                            0.00024-0.00034[a][,c]
                                  4.7-7[b,a]
                                  26 days[a]
                                    CFC-11
                                    1.0[d]
                                    4750[e]
                                  45 years[d]
                                   HCFC-123
                                    0.01[f]
                                     77[e]
                                    1.3[d]
[a] Wang et. al. (undated)
[b] Wang et. al. (2011)
[c] Solstice(TM) 1233zd(E)  SNAP Submission (Anonymous Submitter 2011b)
[d] WMO (2011)
e IPCC 4th Assessment Report (Forster et al. 2007)
[f] Wuebbles and Patten (2009) 

4.	FLAMMABILITY ASSESSMENT
Solstice[TM] 1233zd(E) is not flammable at ambient temperatures and atmospheric pressure, but can ignite when mixed with air under pressure and exposed to strong ignition sources (Anonymous Submitter 2011b). By keeping Solstice[TM] 1233zd(E) away from all sources of ignition and high heat and adhering to the other  precautions listed in the proposed substitute's MSDS, Solstice[TM] 1233zd(E) does not pose a significant flammability risk. 
5.	POTENTIAL HEALTH EFFECTS
To assess potential health risks from exposure to this proposed substitute, the submitter developed an acceptable exposure limit (AEL) of 300 ppm for Solstice[TM] 1233zd(E) (Anonymous Submitter 2012). The AEL represents the maximum 8-hour time weighted average (TWA) at which a worker can be exposed regularly without adverse effects.  EPA also developed a short-term exposure limit (STEL) of 1,000 ppm over a 15-minute period, based on the submitter's 300 ppm AEL value.

According to the MSDS, exposure to Solstice[TM] 1233zd(E) may be harmful by ocular or dermal absorption, inhalation, or ingestion. Exposures of Solstice[TM] 1233zd(E) to the eyes will cause serious eye irritation and may cause frostbite. In case of ocular exposure, the MSDS for Solstice[TM] 1233zd(E) recommends that person(s) should immediately flush the eyes, including under the eyelids, with water for 15 minutes; should frostbite occur, the water should be lukewarm, not hot. Medical attention should be sought if irritation develops or persists. Exposures of Solstice[TM] 1233zd(E) to the skin may cause irritation or frostbite. In the case of dermal exposure, the MSDS for Solstice[TM] 1233zd(E) recommends that person(s) should immediately wash the affected area with water and remove all contaminated clothing; should frostbite occur, person(s) should bathe (not rub) the affected area with lukewarm, not hot, water. If water is not available, cover the affected area with a clean, soft cloth. Medical attention should be sought if irritation develops or persists. 

Solstice[TM] 1233zd(E) vapors are heavier than air and can cause suffocation by reducing oxygen available for breathing, causing asphyxiation at high concentrations.  If person(s) are exposed to high concentrations, the person(s) will likely not realize that he/she is suffocating, but may experience central nervous system effects, such as drowsiness and dizziness. If Solstice[TM] 1233zd(E) is inhaled, person(s) should be immediately removed and exposed to fresh air. The MSDS recommends that if breathing is difficult, person(s) should be given oxygen, provided a qualified operator is present, and medical attention be sought.  Solstice[TM] 1233zd(E) is not likely to be hazardous by ingestion; however, in case of ingestion, the MSDS recommends providing the person(s) with a cup of water, if fully conscious, consulting a physician immediately, and to not induce vomiting without medical advice. EPA's review of the human health impacts of this proposed substitute is contained in the public docket for this decision. 

The potential health effects of Solstice[TM] 1233zd(E) are unlikely to occur when following the exposure guidelines and the ventilation and PPE recommendations outlined in the MSDS for Solstice[TM] 1233zd(E) and this risk screen. 

6.  	OCCUPATIONAL EXPOSURE ASSESSMENT
To ensure that use of the proposed substitute in chillers does not pose an unacceptable risk to workers during manufacturing, installation, servicing, and disposal, occupational exposure modeling at installation was performed for the proposed substitute.  Although modeling is only performed for installation, it is assumed that exposure during servicing and disposal would not exceed exposure during installation. All installation, maintenance, and disposal activities for Solstice[TM] 1233zd(E) chillers are anticipated to occur on-site. Servicing of the chiller is assumed to not exceed exposures during installation and disposal. Installation and disposal are anticipated to have similar exposures, since both require the connection of pipes to transfer the refrigerant; as it is likely that less refrigerant remains in the unit at disposal, it is assumed that installation of a chiller would require transfer of a greater amount of refrigerant, and thus result in greater worker exposure. Thus, occupational exposure was conservatively modeled based on installation.
  
Installation of chillers is expected to occur with limited frequency (up to approximately one event per day) and with limited duration of exposure to the refrigerant charge. Potential exposures to the refrigerant are expected to occur during activities related to charging the refrigerant from the storage tanks into the chiller (e.g., connecting of pipes). Such activities and related exposure is anticipated to occur within 15-30 minutes (per event/day). To evaluate the risk of exposure at installation, the maximum modeled exposure concentration was compared to 900 ppm, the Solstice[TM] 1233zd(E) STEL developed by EPA based on the submitter's 300 ppm AEL value.

The methodology used for this screening assessment is described in Chapter 5 of the Background Document. A box-model approach was used to evaluate potential worker exposure to alternative refrigerants. This approach has been widely used for many years to estimate probable exposures of workers to hazardous airborne materials, and has been described in detail by the National Institute for Occupational Safety and Health (NIOSH).  This model takes into consideration the duration and magnitude of the resulting exposure which is influenced by 1) duration and intensity of the release, 2) rate at which contaminated air is diluted with uncontaminated air, 3) proximity of the worker to the source of the release, and 4) the length of time the worker remains in the affected space.  

The release per event was conservatively assumed to be 1 percent of the equipment charge during installation and then was multiplied by the number of installations estimated to occur over a workday.  One installation per workday was assumed based on data obtained from the Vintaging Model.  The analysis models a refrigerant charge size of 6,000 lbs (2,722 kgs), the maximum charge size indicated by the submitter (Anonymous Submitter 2011a). 

Based on the assumptions described above, the modeling indicates that short-term (15-minute) worker exposure concentrations could reach 917 ppm during installation of Solstice[TM] 1233zd(E), which is slightly above the STEL (900 ppm). However, the 15-minute estimated exposure was derived using conservative assumptions, and represents a worst-case scenario with a low probability of occurrence. These types of systems are typically installed, maintained, and disposed by trained personnel using proper industrial hygiene techniques.   When installing, servicing, or disposing of large chillers, these techniques should be strictly followed.  Adherence to the proposed substitute's MSDS and use of proper engineering controls and PPE make it unlikely that exposure to Solstice[TM] 1233zd(E) would occur. Adequate ventilation should always be established during any use, handling, or storage of Solstice[TM] 1233zd(E). Engineering controls should include vapor-in air detection systems and local exhaust ventilation during use of Solstice[TM] 1233zd(E); filling operations are to occur only at stations with exhaust ventilation facilities. In addition, an eye wash and safety shower should be near the manufacturing facility and ready for use. In general, use of OSHA Category C or higher PPE is recommended, such as respiratory protection chemical splash goggles or face shield, impervious gloves, and chemical-resistant boots and clothing (Anonymous Submitter 2011b, OSHA 1994). A NIOSH-approved positive-pressure supplied-air respirator is recommended where there is insufficient ventilation; self-contained breathing apparatuses should be used for rescue and maintenance work in storage tanks, Contaminated clothing is not to leave the workplace and must be cleaned before reuse (Anonymous Submitter 2011b). Because use of exposure controls and adherence to the appropriate occupational safety guidelines would be followed under good manufacturing practices, as mentioned above, EPA believes that Solstice[TM] 1233zd(E)  does not pose a significant risk to workers during installation, maintenance, and disposal activities.
In addition, there is a risk of generation of toxic decomposition products such as hydrogen fluoride, hydrogen chloride, carbonyl halides, carbon monoxide, and carbon dioxide when Solstice[TM] 1233zd(E) is exposed to fire. Containers of Solstice[TM] 1233zd(E) should not be allowed to contact open flames, glowing metal surfaces, or electrical heating elements. EPA believes that if proper handling and disposal guidelines are followed in accordance with good industrial hygiene and manufacturing practices and the MSDS for Solstice[TM] 1233zd(E), there is no significant risk to workers during the manufacture of Solstice[TM] 1233zd(E).

7. 	GENERAL POPULATION EXPOSURE ASSESSMENT
Solstice[TM] 1233zd(E) is not expected to cause a significant impact on human health in the general population when used as a refrigerant in centrifugal chillers. The compound is proposed for use in closed systems that are operated near atmospheric pressure. General population exposures to ambient air and surface water releases are not expected from this end use. 
8. 	VOLATILE ORGANIC COMPOUND (VOC) ASSESSMENT
Solstice[TM] 1233zd(E) has not been exempted as a volatile organic compound (VOC) under the CAA (40 CFR 51.000), and as such, emissions of Solstice[TM] 1233zd(E) should be controlled.  EPA has received a petition to exempt this compound from the definition of VOC for purposes of regulations in state implementation plans for local air quality because of low photochemical reactivity that would result in insignificant impacts on ground-level ozone; however, Solstice[TM] 1233zd(E) continues to be regulated as a VOC for that purpose unless and until EPA issues a final rule exempting it. 

An assessment was performed to compare the annual VOC emissions from use of Solstice[TM] 1233zd(E) in centrifugal chillers in one year to other anthropogenic sources of VOC emissions. Assuming the submitter's maximum annual production of Solstice[TM] 1233zd(E) for all refrigeration and air-conditioning sector end-uses  (i.e., centrifugal chillers, organic rankine cycle systems, and heat transfer) is entirely released, approximately 45 MT of VOCs would be emitted.  This is approximately equal to 5.6 x10[-1] percent of the VOC emissions caused by the generation of electricity for all refrigeration and air conditioning applications in the United States, or approximately 3.7x10[-4] percent of all anthropogenic VOC emissions in the U.S.  

While these emissions may be significant, release of total production for all refrigeration and air-conditioning end- uses is extremely unlikely to occur. Thus, a secondary analysis was made to determine likely annual VOC emissions from use of Solstice[TM] 1233zd(E) in low-pressure centrifugal chillers. Using leak estimates from the Vintaging Model, the annual release rate (including operating, servicing, and disposal leak rates) was calculated to be approximately 1.0% of the refrigerant charge size. Using these anticipated releases of Solstice[TM] 1233zd(E) from centrifugal chillers, and assuming that the entire production for all refrigeration and air-conditioning end-uses was charged in centrifugal chillers, only 0.5 MT of VOCs would be expected to be released into the atmosphere.  This amount is approximately 5.8x10[-3] percent of the VOC emissions caused by the generation of electricity for all refrigeration and air conditioning applications in the United States, or approximately only 3.9x10[-5] percent of all anthropogenic VOC emissions in the U.S. Further, VOC emissions from manufacture are controlled through standard industry practices, and as such, emissions from the manufacture of the proposed substitute for centrifugal chillers are likely to be further minimized. As VOC emissions from anticipated releases of Solstice[TM] 1233zd(E) are orders of magnitude lower than other anthropogenic sources, the environmental impacts of these VOCs are not considered to be a significant concern.


9.  	REFERENCES
Anonymous Submitter. 2012. Solstice(TM) 1233zd(E) Material Safety Data Sheet. February 28, 2012.
Anonymous Submitter.2011a. Response to Incomplete SNAP Submission for Solstice(TM) 1233zd(E). October 20, 2011.
Anonymous Submitter. 2011b. SNAP Submission to EPA for Solstice(TM) 1233zd(E). May 13, 2011. 
EPA 2011. National Emissions Inventory Air Pollutant Emissions Trends Data. Accessed 23 December 2011. Updated October 2011. Available at: <http://www.epa.gov/ttn/chief/trends/index.html#tables>
EPA 1994.  Significant New Alternatives Policy Technical Background Document:  Risk Screen on the Use of Substitutes for Class I Ozone-depleting Substances: Refrigeration and Air Conditioning.  Stratospheric Protection Division.  March, 1994.

EIA 2011. Annual Energy Outlook 2011 with Projections to 2035. Independent Statistics & Analysis Table Browser. Accessed September 2011. Available online at <http://www.eia.gov/oiaf/aeo/tablebrowser/>.
Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M. Schulz and R. Van Dorland. 2007.  Changes in Atmospheric Constituents and in Radiative Forcing. In: Climate Change 2007:The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

ICF International. 2012. Determination of an Acceptable Exposure Limit (AEL) for HBA-2. Prepared for U.S. Environmental Protection Agency. January 23, 2012.

OSHA. 1994. General description and discussion of the levels of protection and protective gear. 1910.120 App B. Last updated August 22, 1994. Available at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9767

Wang D., Olsen S., Wuebbles D. Undated. "Three-Dimensional Model Evaluation of the Global Warming Potentials for tCFP." Department of Atmospheric Sciences. University of Illinois, Urbana, IL. Draft Report. 

Wang D., Olsen S., Wuebbles D. 2011. "Preliminary Report: Analyses of tCFP's Potential Impact on Atmospheric Ozone." Department of Atmospheric Sciences. University of Illinois, Urbana, IL. September 26, 2011. 

WMO (World Meteorological Organization), 2011. Scientific Assessment of Ozone Depletion: 2010, Global Ozone Research and Monitoring Project -- Report No. 52, 516 pp., Geneva, Switzerland, 2011.

Wuebbles, D.J., and K.O. Patten, Three-dimensional mod - eling of HCFC-123 in the atmosphere: Assessing its potential environmental impacts and rationale for continued use, Environ. Sci. Technol., 43 (9), 3208-3213, doi: 10.1021/es802308m, 2009.
                                  Appendix A:
             Determination of an Acceptable Exposure Limit (AEL) 
                  for Trans-1-chloro-3,3,3-trifluoropro-1-ene

Recommended AEL: 	
1,000 ppm (8-hour time-weighted average)	

Basis and Endpoints:
NOAEC: 4,000 ppm (no significant cardiac histopathology observed at this concentration)

Critical Study:
90-day inhalation toxicity study in the rat (Muijser H., 2011)

Protocol:
Whole-body inhalation, 6 hours/day, 5 days/week for 13 weeks 

Concentrations:
0; 4,000; 10,000; 15,000 ppm

NOAEC:
4,000 ppm (identified by independent pathologist's report [Engelhardt, 2011])

NOAEC [HEC]:
4,000 ppm x 6 hr/8 hr = 3,000 ppm

Uncertainty Factors:
3 (interspecies extrapolation)
3  -  animal to human extrapolation


I.       Introduction
      
Trans-1-chloro-3,3,3-trifluoropro-1-ene has been proposed as a replacement for PFCs, HCFCs, HFCs and other halogenated compounds. It is intended for several end-uses, including as a foam blowing agent, a refrigerant in chillers, a solvent for cleaning in equipment and aerosol cans, and a carrier solvent in adhesives, coatings, and inks.  Several studies assessing the potential toxicity of HBA-2 have been conducted and include the following: 14-day, 28-day, and 90-day inhalation study in rats, developmental inhalation studies in rats and rabbits, a cardiac sensitization assay in beagle dogs, and genotoxicity studies in bacteria and mammalian cells in culture.  The results of these studies are discussed in the following sections to inform an assessment of the potential health risks from human exposure to the study compound in the intended end use.
     
II.       Summary of Toxicity Studies

The toxicological studies reviewed for the determination of acceptable exposure limit for trans-1-chloro-3,3,3-trifluoropro-1-ene are summarized below in Table 1.  Subclinical effects in the heart (monocyte infiltration) associated with inhalation exposure to trans-1-chloro-3,3,3-trifluoropro-1-ene were considered to be the most sensitive human health effects for derivation of an AEL; therefore inhalation studies are described and discussed in detail.  The remaining studies are considered supporting studies.

Table 1.  Trans-1-chloro-3,3,3-trifluoropro-1-ene Toxicological Studies  
                              Inhalation Studies
                                     Doses
                                NOAEL/ NOAEC[a]
                                    Effects
4-hour acute (nose-only, rat)
                                96,000, 156,000
                                and 120,000 ppm
                      LC50, 120,000 ppm (combined sexes)
                   Mortality at 96,000 ppm for some animals.
                           Tremors at all exposures.
14-day (whole body, rat)
                             0, 2,000, 7,500, and
                                  20,000 ppm
                            2,000 ppm (study rpt.)
                            7,500 (peer review)[b]
                Min. focal mononuclear cell infiltrate (heart)
28-day with 14-day recovery (nose-only, rat)
                            0, 2,000, 4,500, 7,500,
                                and 10,000 ppm
                          4,500 ppm[c] (study report)
                           10,000 ppm (peer review)
Increased serum K+ in 7,500-ppm males; reversible changes in hematology/clinical chemistry parameters
90-day study (nose-only, rat)
                        0, 4,000, 10,000 and 15,000 ppm
                            <4,000 (study rpt.) 
                            4,000 ppm (peer review)
                Min. focal mononuclear cell infiltrate (heart)
Rat fetotoxicity
                       0, 4,000, 10,000, and 15,000 ppm
                                  10,000 ppm
                    Dilated urinary bladders in the fetuses
Rabbit fetotoxicity
                       0, 2,500, 10,000, and 15,000 ppm
                                  15,000 ppm
                           No adverse effects noted
Cardiac sensitization, dog
                        25,000, 35,000, and 50,000 ppm
                            Negative at 25,000 ppm
                  Tremors present during exposure 35,000 ppm
                              Supporting Studies
                                     Doses
                                NOAEL/ NOAEC[a]
                                    Effects
In vitro bacterial reverse mutation assay
                       Max concentration of 905,000 ppm
                                      NA
                                   Negative
In vivo unscheduled DNA synthesis
                           0, 7,500, and 10,000 ppm
                                      NA
                                   Negative
In vitro chromosomal aberration assay
                           469, 783, or 1,305 ug/mL
                                      NA
                                   Negative
In vivo micronucleus test (rats)
                    0, 2,000, 4,500, 7,500, and 10,000 ppm
                                      NA
                                   Negative
In vivo micronucleus test (mice)
                                 0, 50,000 ppm
                                      NA
                                   Negative
[a]All values NOAEL/NOAEC unless otherwise reported; NA- not applicable
[b]NOAEC values were revised in a pathology peer review report (Engelhardt, 2011)
[c]NOAEC identified in study report based on clinical chemistry, not histopathology results
NOAEL = No observed adverse effect level (commonly used for oral or dermal exposures)
NOAEC = No observed adverse effect concentration  (commonly used for inhalation exposures)

     
III.       Development of the AEL for Trans-1-chloro-3,3,3-trifluoropro-1-ene 
Several repeated dose inhalation studies assessing the toxic potential of trans-1-chloro-3,3,3-trifluoropro-1-ene were available for development of an AEL. The NOAEC of 4,000 ppm from the 90-day inhalation study was chosen as the point of departure for derivation of an AEL for trans-1-chloro-3,3,3-trifluoropro-1-ene as this was the study with the longest exposure duration with an identifiable NOAEC.

The AEL was calculated in the following manner:

                       4000 ppm x (6/8) / 3 = 1000 ppm

A human equivalent concentration (HEC) was determined by adjusting the NOAEC of 4,000 ppm by the ratio of rat exposure duration per day to that of an occupational worker (6 hours/8 hours). The guidelines for developing Reference Concentration (RfC) values (U.S. EPA, 1994) were followed, which obviated the need to apply a full uncertainty factor (UF) of 3 for pharmacokinetic differences between rats as the animal model of study and humans (a UF of 3 for pharmacodynamic [PD] differences between the two species has been applied). Because subchronic studies are typically used to develop AEL values, an additional UF was not added to account for study duration. Similarly, the database is considered comprehensive, and no additional UF was added to account for database limitations.  

IV.       Inhalation Studies for Trans-1-chloro-3,3,3-trifluoropro-1-ene

Four-Hour Acute Inhalation Study
In an acute 4-hour nose-only inhalation study, male and female Crl:SD (outbred) rats (5/sex) were exposed to three different concentrations  of trans-1-chloro-3,3,3-trifluoropro-1-ene (purity 99.99%) and observed for 14 days post-exposure (when possible) (van Triel, 2009).  In the first group (Group A), animals were exposed to 100,000 ppm trans-1-chloro-3,3,3-trifluoropro-1-ene.  Because of the low toxicity observed, a second group (Group B) of 5/sex were exposed to a target concentration of 125,000 ppm, that actually reached 156,000 ppm due to technical difficulties; all animals died during exposure.  A third group (Group C) of 5 animals/sex were then exposed to a target concentration of 120,000 ppm in an effort to provide more data to identify the LC50.  

One female from Group A died on the first day of the recovery period.  Other animals, male and female, showed clinical signs during recovery, but did not die prematurely.  Necropsy did reveal gray discolored lungs in these animals, which was coincident with petechiae in some cases.   Three males and two females of Group C died during exposure. Necropsy of these animals revealed reddish lung, with some also being enlarged.  In two female animals of group B, red spots were also found on the thymus.  In animals sacrificed on schedule following recovery, no other abnormalities were found. The combined-sex LC50 was reported as 120,000 ppm.

Fourteen-Day Inhalation Study
In a dose-range-finding inhalation study, Crl:CD(SD) rats (5/sex/group) were exposed via whole body inhalation to 0, 2,000, 7,500, or 20,000 ppm trans-1-chloro-3,3,3-trifluoropro-1-ene (99.9% pure) (Staal, 2008).   Exposures were for 6 hr/day, 5 days/week, in a 2-week period (10 total exposure days).  Clinical signs, body weights and food consumption data were collected.  Blood samples were drawn at the end of each week for hematology and clinical chemistry analyses. Gross necropsies were performed on all animals following the last exposure, and organs were collected and weighed; select organs, including the respiratory tract, were processed and analyzed histologically.  

The only clinical sign reported during exposure was restlessness, particularly in the highest concentration; the effect resolved after 15 minutes of exposure.  Test-compound exposure did not induce changes in body weights or food consumption.  Regarding changes in hematology, the study author noted an increase in prothrombin time in females at 20,000 ppm, and an increase in absolute and relative numbers of monocytes and absolute number of neutrophils in males at 20,000 ppm.  Increases in serum liver enzymes (ALAT and ASAT in males at 20,000 ppm) were not confirmed by any changes in liver histopathology, and were thus considered not toxicologically relevant.  Histology revealed multifocal mononuclear cell infiltrates, identified by the study laboratory in animals at 7,500 and 20,000 ppm.  However, following an independent pathological review of the histology slides of the heart tissues (Engelhardt, 2011), many of the lesions originally identified by the study laboratory as `very slight' or `slight focal myocardial mononuclear cell infiltrate' were downgraded to being `not remarkable' or were noted to be located only in the apex of the heart.  According to the reviewing pathologist, lesions in the apex and/or adjacent portions of the right and left ventricles and interventricular septum of the heart in rats with such lesions are "typical of rodent spontaneous cardiomyopathy".  Given the revised heart data, the reviewing pathologist increased the NOAEC to 7,500 ppm from the original NOAEC of 2,000 ppm identified by the study laboratory.  ICF accepts the revised value as reasonable, given the expertise of the reviewing pathologist.

Four-Week Inhalation Study
In a longer-term, nose-only, multi-exposure study, five groups of Sprague-Dawley rats were exposed 6 hrs/day, 5 days/week in a 28-day period (e.g., 20-21 exposure days) to the following nominal concentrations of trans-1-chloro-3,3,3-trifluoropro-1-ene (99.9% pure): 0, 2,000, 4,500, 7,500, and 10,000 ppm (Staal, 2009).  Additional groups of 5/sex were exposed to either 0 or 10,000 ppm in an identical fashion, followed by a 14-day recovery period. The following parameters were measured in accordance with harmonized guidelines for this repeat-exposure study: clinical signs and mortality, food consumption and body weights, hematology and clinical chemistry, gross necropsy, organ weights, and histopathology of select organs.

The study compound did not induce any changes in clinical signs or mortality, food consumption, body weights, urinalysis parameters, gross necropsy, or organ weights.  In contrast to the histopathological findings from the 14-day study, no mononuclear cell infiltration was noted in cardiac tissue or any other selected organ.  An increase in the relative number of basophils was observed in males at 10,000 ppm, which resolved in the 14-day recovery period.   Changes in clinical chemistry parameters were limited to decreased creatinine in males at 10,000 ppm, which also was resolved at the end of the recovery period; and an increase in serum potassium in males at both 7,500 and 10,000 ppm, which were still slightly elevated after recovery, although not statistically significant.  The study authors identified a NOAEC of 4,500 ppm, arguing that the increased potassium levels at exposure concentrations of 7,500 and 10,000 ppm were related to treatment. The pathologist who performed the peer review of the cardiac histopathology slides for this study identified a NOAEC of 10,000 ppm, based on the confirmed absence of compound-induced subcellular damage to cardiac tissue.  ICF concurs with the reviewing pathologist, and would add that although the increased potassium level observed at >=7,500 ppm may be indicative of subclinical cardiotoxicity, it cannot be attributed to the test compound alone, and may also be attributed to spontaneous cardiomyopathy.  The NOAEC for this study is set, therefore, at 10,000 ppm.

Ninety-Day Inhalation Study
In a 90-day inhalation study, male and female Sprague-Dawley (Crl:CD[SD]) rats (10/sex/concentration) were exposed to trans-1-chloro-3,3,3-trifluoropro-1-ene (99.9% purity) via nose-only exposure at nominal vapor concentrations of 0, 4,000, 10,000, or 15,000 ppm for 6 hrs/day for 5 days/week for 13 weeks, for a total of 65 exposure days (Muijser, 2011).   Rats were observed twice daily for clinical signs of toxicity, morbidity, and mortality. Body weights and mean food consumption were recorded weekly. Ophthalmoscopic examinations were conducted at study initiation and during the last week of exposure. Blood samples and urine samples were taken just prior to or the last day prior to sacrifice at the end of the exposure period and were analyzed for hematology, clinical chemistry and urinalysis parameters consistent with harmonized guidelines.  Gross necropsies were performed on all surviving animals after the scheduled exposure period, and select organs were removed, weighed, and prepared for histopathology.    

Mortality, Clinical Effects, Eye Effects, Food Consumption, Body Weights
Exposure to the study compound did not induce early mortality or any observed clinical abnormalities.  In addition, exposure did not affect body weight gain, food consumption, or changes in eye condition.


Hematology/Clinical Chemistry
Effects on hematological parameters were limited.  For example, exposure to the study compound had no effect on red blood cell parameters and affected white blood cells only by decreasing the relative number of lymphocytes in males at 15,000 ppm.  Clinical chemistry effects were inconsistent between the sexes.  Plasma of ASAT and ALAT were increased at statistically significant levels in males at 15,000 ppm, but not in females, while glucose and urea were increased in females at 10,000 and 15,000 ppm, but not in males.  High-concentration females also exhibited significantly increased potassium and decreased triglyceride levels.  No other changes in measured analytes were noted.

Organ Weights
A treatment-related decrease in absolute and relative heart weights was noted in male rats, which reached statistical significance at the highest concentration (15,000 ppm).  In addition, relative liver weights in the males were significantly increased at the highest concentration, whereas by contrast, the relative liver weights of high-concentration females were significantly decreased.  No other changes in organ weights were noted.

Macroscopic and Microscopic Findings
Exposure to trans-1-chloro-3,3,3-trifluoropro-1-ene did not induce any changes in the appearance of organs or tissues in the bodies of rats evaluated following gross necropsy.  In general, no compound-induced effects were noted upon analyses of histopathology findings, with the exception of minimal multifocal mononuclear cell infiltrate in the heart.  The study authors also identified inflammation occurring coincident with the infiltrates in some animals.  The report of the peer review pathologist indicated that the vast majority of these findings were downgraded to categories of `not remarkable' or were localized to the apex, the lower left ventricle, or the atrium.  Again, because of the downgrading of incidences of infiltration reported in the original study, and the identification of some mononuclear infiltration as `spontaneous cardiomyopathy,' the NOAEC was identified as the lowest exposure concentration of 4,000 ppm (the study authors reported the NOAEC as less than 4,000 ppm).  ICF concurs, and as such, the NOAEC used in the determination of an AEL for trans-1-chloro-3,3,3-trifluoropro-1-ene is 4,000 ppm.

Developmental Toxicity
Trans-1-chloro-3,3,3-trifluoropro-1-ene was evaluated in two developmental toxicity studies, one in rats and one in rabbits.  

Rat Prenatal Developmental Study
In the prenatal developmental study in rats (Waalkens-Berendsen and van den Hoven, 2011), groups of 24 mated female Wistar (Crl:WI[WU]) rats were exposed 6 hrs/day to concentrations of 0, 4,000, 10,000 or 15,000 ppm trans-1-chloro-3,3,3-trifluoropro-1-ene (99.9% pure) from gd 6 to gd 19.  Health parameters measured during the in-life phase of the study included mortality, clinical signs, maternal body weight, and food consumption.  A Caesarean section was performed following the gestation period, and females and fetuses were evaluated via gross necropsy, and for standard reproductive toxicity endpoints (e.g., gestation index, fecundity index, fetus sex ratio, number of corpora lutea, implantation sites, pre- and post-implantation loss, live and dead fetuses, and resorptions).  Fetuses, placentas and reproductive organs were weighed, and fetuses were processed for soft tissue and skeletal abnormalities and malformations.

Exposure to the study compound did not affect any of the measured parameters with the exception of the following: a statistically significant increase in the incidence of dilated urinary bladders was observed in the fetuses of the highest concentration group (15,000 ppm).  Because the incidence of this anomaly increased with higher concentrations, it is considered treatment-related.  No signs of maternal toxicity were noted at any concentration.  The NOAEC for developmental effects is established at 10,000 ppm; the NOAEC for maternal toxicity is established at 15,000 ppm.

Rabbit Prenatal Developmental Study
Trans-1-chloro-3,3,3-trifluoropro-1-ene was further evaluated in a developmental study in the New Zealand white rabbit.  Hoffman (2010) exposed 22 pregnant dams/group during organogenesis (gd 6 to gd 28) to trans-1-chloro-3,3,3-trifluoropro-1-ene (~100% purity) via whole-body inhalation for 6 hrs/day at concentrations of 0, 2,500, 10,000 or 15,000 ppm.  During the in-life phase of the study, the rabbits were observed for mortality, clinical signs, body weights, and food consumption.  Following euthanasia of the dams at gd 29, the following parameters were measured: gross necropsy, number of corpora lutea and implantation sites, uterine and placental weights, fetus number (live), fetal weights (live only), sex ratio, external defects, soft tissue abnormalities, and skeletal abnormalities and state of ossification.  

Exposure to the test compound did not affect any changes in any of the measured parameters of the exposed dams or the fetuses.  Therefore, the NOAEC for both maternal and fetal toxicity is established at 15,000 ppm in this rabbit developmental assay.

Cardiac Sensitization
In a muzzle-only, acute exposure study in young beagle dogs (Atterson, 2011), 6 male dogs were exposed successively to 25,000 ppm (2.5%), 35,000 ppm (3.5%) and 50,000 ppm (5%) trans-1-chloro-3,3,3-trifluoropro-1-ene (99.978% pure) up to a maximum period of 33 minutes, with 48 hours of rest occurring in between exposure periods.  Control (air) exposures occurred in the same dogs.  For the cardiac sensitization, epinephrine challenge (bolus) injections, ranging from 2 to 8 ug/kg, were started approximately 5 minutes following the initiation of exposure and continued until termination of exposure. Only 2 of the 6 dogs were exposed to the highest trans-1-chloro-3,3,3-trifluoropro-1-ene concentration, because behavioral responses (vocalization, injected sclera, excessive salivation, tremors, convulsions and/or reddened gums) prompted the termination of exposure; only one of the dogs at this concentration was given an epinephrine challenge.

No test-related deaths occurred in the study.  Clinical findings similar to those at 50,000 ppm were noted after exposure to 35,000 ppm (tremors, injected sclera, reddened ears and excessive salivation). No signs of cardiac sensitization were noted at 25,000 or 35,000 ppm; however, the presence of ECG noise in two animals exposed to 35,000 ppm precluded the complete characterization of cardiac sensitization at this concentration.  As noted previously, exposure was terminated at the highest concentration and assessment of cardiac sensitization was not possible at this level.  Therefore, the results indicate that the study compound does not cause cardiac sensitization at 25,000 ppm.

V.       Supporting Genotoxicity Studies for Trans-1-chloro-3,3,3-trifluoropro-1-ene

Reverse Mutation Assay
Trans-1-chloro-3,3,3-trifluoropro-1-ene was tested in an Ames bacterial reversion assay in Salmonella typhimurium (S. typhimurium) strains TA98, TA100, TA1535, TA1537, and E. coli strain WP2 uvrA (Wagner et al., 2011).  This assay measures the ability of the compound to induce either base pair or frame shift mutations in DNA in the presence or absence of S9 fraction from induced rat livers (metabolizing enzymes including mixed function oxidases).  The study compound was analyzed for mutagenicity twice at concentrations ranging from 73,400 to 905,000 ppm at 25°C for either 24 or 48 hours.  Appropriate negative and positive controls were analyzed in the same assays.  Mutagenicity was not induced in any strain, but toxicity was seen in all strains at the top two concentrations of 513,000 and 905,000 ppm.  A confirmatory assay was performed using slightly reduced exposure concentrations of 17,200; 24,500; 73,400; 147,000; 196,000; 269,000; 513,000 and 905,000 ppm at 25°C.  Cytotoxicity was observed at the top two concentrations, as in the previous assays.  No positive responses were observed with strains TA98 and TA1537 in the absence of S9 activation and with strains TA98 and WP2uvrA in the presence of S9 activation.  The compound is categorized as negative in this genotoxicity assay.
 
Unscheduled DNA Synthesis
Trans-1-chloro-3,3,3-trifluoropro-1-ene was tested for the ability to induce unscheduled DNA synthesis in liver hepatocytes isolated from male rats exposed to 7,500 and 10,000 ppm of the study compound in a 28-day study (Staal, 2009).  The control group was the same one used in the 28-day study and positive control animals were dosed with standard toxicants per harmonized guidelines.  Trans-1-chloro-3,3,3-trifluoropro-1-ene did not induce unscheduled DNA synthesis under the conditions used in the 28-day study, and is categorized as negative for this genotoxicity assay.

Micronuclei
Two studies were performed to assess the ability of trans-1-chloro-3,3,3-trifluoropro-1-ene to include micronuclei in bone marrow, as described below. 

Micronuclei Rat Study
Trans-1-chloro-3,3,3-trifluoropro-1-enewas tested for the ability to induce micronuclei in bone marrow cells isolated from male rats exposed to 0, 2,000, 4,500, 7,500 and 10,000 ppm of the study compound in a 28-day study (Staal, 2009).  Appropriate positive control animals were dosed with standard toxicants per harmonized guidelines.  The test compound did not induce chromosomal damage or induce micronuclei in the bone marrow under the conditions used in this study (the maximum concentration administered, 10,000 ppm is equivalent to >12,000 mg/kg, much higher than the 1,000 mg/kg limit dose recommended by EPA) and is judged negative for this genotoxicity assay.

Micronuclei Mice Study
Trans-1-chloro-3,3,3-trifluoropro-1-enewas tested in an independent assay for its ability to induce micronuclei in the bone marrow of male mice (de Vogel, 2009).  Two groups of 10 male, albino mice (CD-1 strain, Charles River) were exposed for a single, nose-only, 4-hour exposure to trans-1-chloro-3,3,3-trifluoropro-1-ene (99.99% pure) at concentrations of 0, or 50,000 ppm.  Five male mice were injected intraperitoneally with 0.75 mg/kg-bw of mitomycin C as a positive control for comparison.  Bone marrow cells were isolated from half the exposure group at 24 hours and the remainder at 48 hours post-exposure; bone marrow smears were prepared and analyzed for the presence of polychromatic and normochromatic erythrocytes and micronuclei in a manner consistent with established guidelines.  The test compound did not induce micronuclei or any other form of chromosomal damage and was thus judged negative in this genotoxicity assay.  


Chromosomal Aberration
Trans-1-chloro-3,3,3-trifluoropro-1-ene (99.98% pure) was tested in a chromosomal aberration assay with human lymphocytes cultured in vitro (Pritchard and Damant, 2011).  Human lymphocytes, isolated from whole blood samples provided by volunteers, were treated with trans-1-chloro-3,3,3-trifluoropro-1-ene for either 3 or 21 hours at doses of 469, 783, or 1,305 ug/mL in the presence or absence of metabolic activation (S9 from the livers of chemically-induced rats). Trans-1-chloro-3,3,3-trifluoropro-1-ene was determined to be negative in this genotoxicity assay, as the cells treated with trans-1-chloro-3,3,3-trifluoropro-1-ene in all experiments did not cause an increase in the frequency of cells exhibiting structural chromosomal aberrations compared with negative controls at any concentration tested.

References

Atterson PR. 2011. Acute cardiac sensitization study of 1233zd in beagle dogs.  WIL Research Laboratories, LLC, Ashland, OH, performed for Anonymous Submitter, NJ. 21 April 2011.
de Vogel N and van Triel JJ. 2009.  Micronucleus test in bone marrow cells of mice treated with 1233zd(E), administered by inhalation.  TNO Quality of Life, The Netherlands, performed for Anonymous Submitter, NJ, 10 February 2009.
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Hoffman G. 2010.  1233zd(E): Embryo-fetal toxicity study in rabbits via whole-body inhalation exposure (GLP).  Huntingdon Life Sciences, New Jersey, for Anonymous Submitter, New Jersey. 2 September 2010.
Muijser H. 2011.  Sub-chronic (13-week) inhalation toxicity study with 1233zd(E) in rats. TNO Quality of Life, The Netherlands, performed for Anonymous Submitter, NJ, 3 May 2011.
Pritchard L and Damant C. 2011.  1233zd in vitro mammalian chromosome aberration test in human lymphocytes. Amended Final Report. Huntingdon Life Sciences UK for Anonymous Submitter NJ, 31 March 2011.
Staal YCM. 2009.  A sub-acute (4-week) inhalation toxicity study, including unscheduled DNA synthesis and micronucleus test, with 1233zd(E) in rats. TNO Quality of Life, The Netherlands, performed for Anonymous Submitter, USA, 27 May 2009.
Staal YCM. 2008. Sub-acute (14-day) inhalation toxicity study with 1233zd(E) in rats. TNO Quality of Life, The Netherlands, performed for Anonymous Submitter, USA, 15 December 2008.
U.S. EPA. 1994. Methods for Derivation of Inhalation Reference Concentrations (RfCs) and Application of Inhalation Dosimetry. U.S. Environmental Protection Agency, Office of Research and Development, Office of Health and Environmental Assessment, Washington, DC, EPA/600/8-90/066F.
van Triel JJ. 2009.  Acute (4-hour) inhalation toxicity study with 1233zd(E) in rats.  TNO Quality of Life, The Netherlands, performed for Anonymous Submitter, USA, 17 February 2009. 
Waalkens-Berendsen DH, and MJW van den Hoven. 2011.  A prenatal developmental inhalation toxicity study with HCFO-1233zd(E) in rats.  TNO Triskelion, The Netherlands, for Anonymous Submitter, New Jersey, 28 January 2011.
Wagner VO, Hines RM, Jois M. 2008. 1233zd(E) bacterial reverse mutation assay using gas-phase exposure. Amended Final Report. BioReliance, Rockville, MD, performed for Anonymous Submitter, NJ. 27 April 2011.

