1 May 26, 2009 

## Significant New Alt ernatives Policy Program Refrigeration and Air Conditioning Sector Risk Screen on Substitutes for CFC - 12, HCFC - 22 , and R- 502 in Retail Food Refrigeration . Substitute: Propane This risk screen contains no Clean Air Act (CAA) Confidential Business Information (CBI) and, therefore, may 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 decade, 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, is developing a program to evaluate the human health and environmental risks posed by alternatives to ODS. The main purpose of EPA's program, called the Significant New Alternatives Policy (SNAP) Program, is to identify acceptable and unacceptable substitutes for ODS in specific end uses. EPA’s decision on the acceptability of a substitute is based largely 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 maj or 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 report is to supplement EPA’s Background Document on the refrigeration and air conditioning sector (EPA 1994) (hereinafter referred to as the Background Document) by adding to the lis t of potential substitutes for specific end

-uses of CFC
- 12 , HCFC
- 22 and R
- 502 in this sector. The proposed end

-use application considered in this analysis is retail food refrigeration, specifically ice cream cabinets. The specific proposed CFC
- 12 , HCFC
- 2 2 and R
- 502 substitute examined in this report is propane (R

- 290). The substitute would only be used in new equipment, not in retrofitted equipment. The proposed substitute, propane, may contain minute quantities of impurities. Table 1 details the im purities which may be present in the substitute and notes the maximum estimated concentrations of these impurities. Table 1 . Composition of the Substitute . Substitute Percent by Weight Propane  99.5 % Potential Impurities Maximum Concentration (ppm v/v) Ethane 1700 Propylene 300 n - Butane 1000 Sulphur 1 Water 122 May 26, 2009 The potential risks associated with use of substitutes in retail food refrigeration 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. Presently, EPA’s SNAP Program has not approved any hydrocarbon s as a substitute in retail food refrigeration end uses. Of particular concern are the flammabi lity risks associated with hydrocarbon s during manufacturing, use, servicing, and disposal of retail food refrigeration appliances. Occupational exposure modeling was performed to ensure that use of the proposed substitute in the application listed above did not pose unacceptable risk to workers during equipment manufacture

. Modeling was p erformed at the end

-use to ensure that potential catastrophic releases of the substitute did not pose unacceptable risk to store employees and customers in locations whe re the ice cream cabinet s are in use . Lastly, general population exposure modeling was performed to ensure that the proposed substitute would not pose unacceptable risk to the population at large. Section 2 of this report summarizes the results of the risk screen for the proposed substitute. The remainder of the report is organized into the following sections:

 Section 3: Atmospheric Assessment  Section 4: Flammability Assessment  Section 5: Asphyxiation Assessment  Section 6: Toxicity Assessment  Section 7: Volatile Organic Compound Assessment  Section 8: References 

### 2. SUMMARY OF RESULTS Propane is recommended for SNAP approval for retail ice cream cabinets. EPA's risk screen indicates that the use of the proposed substitute will be less harmful to the atmos phere than the continued use of CFC
- 12 , HCFC
- 22 and R
- 502 . No significant toxicity risks to workers, consumers, or the general population are expected according to occupational and end

-use exposure modeling. Flammability models indicate that risks of explosions are not a concern for store employees or customers . To further protect against the limited risk of explosion, it is recommended that the cabinets not be used in small, poorly ventilated spaces (see Section 4). Caution must be used in manufacturi ng facilities and by refrigeration technicians to minimize explosion risk while in the presence of large quantities of the substitute. This includes installation of proper safety equipment during manufacturing , transportation, and storage and providing pr oper training and certification to technicians. EPA recommends that American Society of Heating, Refrigerating and Air

- Conditioning Engineers (ASHRAE) Standards 15 and 34 be followed. 

### 3. ATMOSPHERIC ASSESSMENT This section presents an assessment of the potential risks to atmospheric integrity posed by the use of propane in the retail food refrigeration sector. The ODP, GWP, and atmospheric lifetime (ALT) of the proposed substitute are presented in Table 2. The environmental impacts resulting from use of pro p ane are generally in the range of those predicted for other substitutes examined in the Background Document. The substitute is substantially less harmful to the ozone layer, has less climate impact, and a shorter atmospheric lifetime compared to CFC
- 12 , HCFC
22 and R
- 502
.3 May 26, 2009 Table 2 . Atmospheric Impacts of Propane Compared to CF C - 12 , HCFC - 22 and R- 502 . Refrigerant Ozone Depleting Potential (ODP) Global Warming Potential (GWP) Atmospheric Lifetime years (ALT) Propane 0 a  3 a <1 b CFC
- 12 1 c 8,100 d 100 c HCFC
- 22 0.055 c 1,500 d 12 c R
- 502 e 0.33 5,478 NA NA = Not Available a Propane SNAP Submission (Ben and Jerry’s/Unilever 2008). b Atmospheric lifetime (ALT) not provided in SNAP submission. Wuebbles (2003) indicates that propane ha s an ALT of 5

– 21 days

. c Available at: http://www.epa.gov/ozone/ods.html. d IPCC, Second Assessment Report (1996). e R
- 502 is a blend consisting of HCFC
- 22 (49% ) and CFC
- 115 (51%). The ODP and GWP presented for this blend were calculated using values from http://www.epa.gov/ozone/ods.html and IPCC ’s Second Assessm ent Report (1996), respectively. 

### 4. FLAMMABILITY ASSESSMENT Propane is flammable when its concentration in air is in the range of 2.1%

- 9.5% by volume (this is equal to 21,000 ppm to 95,000 ppm). In the presence of an ignition source (e.g., static electricity, a spark resulting from a closing door, or a cigarette), an explosion or a fire could occur when the concentration of propane is within these flammability limits

. The remainder of this section addresses the potential for flammability risks at the end

-use, and during manufacture and servicing and provides a discussion of measures to be taken to ensure safe use

. The proposed use of this substitute is in ice cream cabinets which could reasonably be expected to be located either in the main area of a store, or in a storage room. Because a storage room could be much smaller than the main area of a store, a reasonable worst

- case scenario analysis was performed to model catastrophic release of the refrigerant in a storage room. For the analysis, a storage room with a volume of 42 m3 was assumed. 1 In the analysis, the full charge 2 of the unit is assumed to be emitted over the course of one minute and the model conservatively assumes 2.5 air exchange s occur per hour. Horizontal stratification is also assumed since propane is denser than air and will settle in higher concentrations closer to the ground. In order to simulate the horizontal concentration gradient that will occur because of the weight differential between the refrigerant and air, it is assumed that 95 percent of the leaked refrigerant mixes evenly into the bottom 0.4 meter of the room, and the rest of the refrigerant mixes evenly in the remaining volume (Kataoka 1999). Under catastrophi c release scenarios, 3 the maximum instantaneous concentration of propane in the lower stratum of the room would be approximately 66 percent of its lower flammability limit ( LFL ) for the room size assumed, as shown in Table 3 . T he maximum instantaneous con centration is lower in the upper stratum of the room, as only five percent of the leaked refrigerant is present in this stratum, and this stratum has a greater volume than the lower stratum

. For flammability to be of concern under the conservative (protec tive) assumptions described above, the volume of the storage room would have to be 28.5 m3 (1,006.5 ft 3 ). Assuming a square room with a ceiling height of 3 m (9.8 ft), this equates to a 3.1 x 3.1 m (10.1 x 10.1 ft) storage room. As storage rooms can be o f varying size, and because boxes and

1 This room was considered a ‘high risk room’ due to its small size and poor ventilation. (Ben and Jerry’s/Unilever 2008) 2 The charge size used in al l models in this analysis is 150g of propane. The submitter notes that the cabinets will have a charge size of about 90g; however the maximum charge will be 150g (Ben and Jerry’s/Unilever 2008). To ensure all models address a r easonable “worst - case,” the maximum charge size was chosen for use in the models. 3 The submitter notes that “catastrophic leaks during operation have not been recorded.”4 May 26, 2009 other equipment in the room may reduce the effective volume of the room, it is therefore recommended that propane cabinets not be installed in small, poorly ventilated spaces, to avoid the risk of fire and explosion. However, for average sized rooms the risk of explosion is minimal. Cutting a hole in the bottom of storage room doors (to act as a vent and increase air circulation) and t he installation of leak prevention devices would further protect against the limited risk of explosion. For example, in commercial refrigeration end

-uses, refrigerant leak prevention systems can be used to capture leaked refrigerant in a receiving tank during over pressure events, rather than venting the refrigerant to the atmosphere. 4 Additionally, in motor vehicle air

- conditioning, an outflow prevention device can be used to prevent leakage events when the heat exchanger of a unit is damaged. 5 ICF recommends that similar safety devices be installed within units containing propane to further reduce the risk of explosion. Table 3 . Flammability Assessment
Room Type/Appliance Type Reasonable Worst - Case Scenario Flammability Threshold Scenario

Room Size (m 3 ) Maximum

Instantaneous Concentration (ppm) a,b Room S ize (m 3 ) Maximum Instantaneous Concentration (ppm) a,b Storage Room/Ice Cream Cabinet 42 (1,483 ft 3 ) 13,780 28.5 (1,006.5 ft 3 ) 20,308

a Lower Flammability Limit of propane is equal to 21,000 ppm b Values provided in these columns refer to the concentrat ion in the lower stratum of the room. Catastrophic releases of large quantities of refrigerant during servicing and manufacturing, especially in areas where large amounts of refrigerant are stored, could cause an explosion. For this reason, it is important that only properly trained and certified refrigerant technicians handle propane . The submitter has provided information regarding their training program for service technicians . The program includes detailed information covering important t opics such as potential ignition sources, proper tools to use with flammable refrigerants, safe workplace behavior and service procedures

. At the end of the training , technicians must pass a multiple choice assessment (Ben and Jerry’s/Unilever 2008)

. A ll technicians who will be servicing cabinets using propane should receive this training and be required to pass the assessment
. As a further precaution, propane storage and transport equipment should be installed with safety devices that minimize the likel ihood of catastrophic releases. For example, NFPA 58 Liqu e fied Petroleum Gas C ode (NFPA 200 8 ) requires the use of overfill protection devices (OPD) on cylinders to minimize the likelihood of leaks. The NPFA 58 Code also contains storage and transportatio n requirements/guidelines. Similar equipment safety and procedural requirements should be implemented for this substitute

. It is important that the strictest standards be followed during the manufacture of these ice cream cabinets

. Itis recommended that refrigerants be properly stored and caution used within manufacturing facilities to minimize explosion risk and that worker s adhere to the requirements set by OSHA under 29 CFR 1910. OSHA requirements include proper ventilation and storage practices w ithin manufacturing facilities to prevent fire and explosion. Proper ventilation should be maintained at all times during the manufacture of equipment containing propane through adherence to g ood manufacturing p ractices . If refrigerant levels in the air s urrounding the equipment rise above one

- fourth of the lower flammability limit , 6 the space should be evacuated and re

- entry should only occur after the space has been properly ventilated. 

### V entilation is also of the utmost importance to mitigate the risk o f fire or explosion when servicing equipment using propane . During servicing operations, technicians should ensure that proper ventilation is in place

4 http://www.freepatentsonline.com/5259204.html 5 http://www.freepatentsonline.com/ 6966365.html 6 OSHA regulation 29 CFR 1910.110 considers ventilation adequate “when the concentration of the gas in a gas

- air mixture does not exceed 25 percent of the lower flammable limit.”5 May 26, 2009 through the use of fans (or other mechanical ventilation devices) and portable refrigerant detectors should be used to alert technicians to the presence of flammable gases in the area. 

### 5. ASPHYXIATION ASSESSMENT The risk of asphyxiation for a reasonable “worst
- case” scenario was investigated for propane . This analysis considers the same small storage room as in Section 4
. This analysis does not consider conditions that are likely to occur that would reduce the levels to which individuals would be exposed, such as open doors or windows, fans operating, conditioned airflow (e ither heated or cooled), or even seepage between the door and door frame. T he maximum charge of propane necessary to reduce the oxygen levels to 1 2 percent in air , 7 in a storage room of volume 42 m3 ( 1,483 ft 3 ), was calculated, assuming horizontal stratification of the refrigerant and the air. Horizontal stratification is assumed since propane is denser than air and will settle in higher concentrations closer to the ground. Assuming that nitrogen and oxygen retain the same relative volumes in the rooms with the balance composed entirely of propane , and that the pressure of the room does not increase significantly with the addition of the refrigerant, a charge of approximately 904 g would be necessary to reach 12 percent oxygen in the lower stratum. This amount represents more than six ti mes the maximum intended charge of approximately 1 5 0 g for a single propane ice cream cabinet. Charge requirements to reach the same effect in the upper strata would be even higher because of the stratum’s larger volume

. For asphyxiation to be of concern with the proposed charge size, under the conservative (protective) assumptions described above, the volume of the storage room would have to be about 6.96 m3 ( 245.8 ft 3 ). Assuming a square room with a ceiling height of 3 m (9.8 ft) , this equates to a 1.5 x 1.5 m ( 5 x 5 ft) storage room . The results of the asphyxiation assessment are summarized in Table 4 below. EPA does not believe that the use of propane in this end

-use poses a significant risk of asphyxiation or impaired coordination to store employe es or customers
. Table 4 . Asphyxiation Assessment Room Type/Appliance Type Appliance

Charge (g) Reasonable Worst - Case Scenario Asphyxiation Threshold Scenario

Room Size (m 3 ) Charge Causing

Impairment (g) a Room Size (m 3 ) Charge Causing Impairment (g) a Storage Room/ Ice Cream Cabinet 150 42 (1,483 ft 3 ) 904 6.96 ( 245.8 ft 3 ) 15 0

a Values provided in these columns refer to the charge required to cause impairment in the lower stratum of the room. 

### 6. TOXICITY ASSESSMENT 6.1 TOXICITY REFERENCE VALUES To assess potential health risks from exposure to this substitute in the retail food refrigeration sector, EPA identified the relevant toxicity threshold values for comparison to modeled exposure concentrations for different scenarios. For the occupational exposure analysis, potential risks from chronic and acute worker exposure were evaluated by comparing exposure concentrations to available occupational exposure limits. Occupational exposure limits are typically established for either an eight

-hour or ten -hour time period for long

- term exposure, such as the Workplace Guidance Levels (WGLs), or for a 10 to 30

- minute period for short

- term exposure, such as the Emergency Guidance Levels (EGLs), as shown in Table 5

. Because they are designed to assess risks from acute exposure, emergency guidance levels are used to assess risks from

7 Twelve percent oxygen in air is the NOAEL for hypoxia (ICF 199 7).6 May 26, 2009 short

- term consumer exposures. Reference concentrations (RfCs) are used to assess risks to the general population from exposure to ambient air releases and to as sess potential risks associated with chronic consumer exposures. A list of the relevant toxicity limits is shown in Table 5 . Table 6 provides definitions for acronyms used in Table 5. EPA’s approach for identifying or developing these values is discusse d in Chapter 3 of the Background Document.

Table 5 . Toxicity Levels of Propane and Potential Impurities Long - term Exposure ppm Short - term Exposure ppm Reference Concentration (RfC) mg/m 3 Substitute Propane 1000 a

(OSHA PEL/NIO SH REL) 2100 a (IDLH) 0.9 b

Potential Impurities Ethane NA c NA c NA Propylene NA d NA d NA n - Butane 800 e (NIOSH REL) NA 0.95 b Sulphur NA NA NA NA = Not Available a "Based on acute inhalation toxicity data in humans (ACGIH 1991; Braker 1980), a va lue much greater than 10,000 ppm would have been appropriate. However, the revised IDLH for propane is 2,100 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 2.1 %)." (NIOSH 1996) b SNAP Refrigerant Background Do cument (EPA 1994). c Ethane is a "simple asphyxiant." http://www.osha.gov/dts/chemicalsampling/data/CH_238900.html d Propylene is a "simple asphyxiant." http://www.osha.gov/dts/chemicalsampling/data/CH_264442.html e http://www.cdc.gov/niosh/npg/npgd0068.h tml

Table 6 . Explanation of Toxicity- Related Acronyms a Organization Definition OSHA Occupational Safety and Health Administration NIOSH National Institute for Occupational Safety and Health Exposure Limit Definition Explanation IDLH Immediately Dangerous to Life and

Health If exposed to this concentration, room occupants are expected to be able to escape the room within 30 minutes without experiencing escape
impairing or irreversible health effects. PEL Permissible Exposure Li mit This is an 8
- hour time
- weighted average exposure limit set by OSHA. REL Recommended Exposure Limit This is a 10
- hour time
- weighted average exposure limit set by NIOSH. RfC Reference Concentration A concentration “designed to protect the general popu lation against adverse systemic (i.e., noncancer) effects.” aAll information in this table taken from EPA (1994)

. 6.2 OCCUPATIONAL EXPOSURE Occupational exposure modeling was performed for the proposed substitute to ensure that use of the substitute does not pose an unacceptable risk to workers. The methodology used for this screening assessment is based on the one used in the occupational exposure and hazard analysis described in Chapter 5 of the Background Document. A box

- model approach was used to eva luate 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 Occup ational 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 the7 May 26, 2009 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. Estimates of refrigerant release per event for various release scenarios and data on number of events were obtained from the Vintaging Model. 8 T he release per event was conservatively assumed to be 1 percent of the equipment charge during manufacturing and 3 percent of the equipment charge during disposal. 9 The release rate per event was multiplied by the number of events estimated to occur over a workday. For equipment manufacturing, the number of events per workday was assumed to equal the number of units containing the substitute produced per plant per year divided by 365 workdays per year. For the purposes of this model , it is assumed that propane will have a market penetration rate of 23 % 10 and that one production facility will be in operation. These assumptions result in approximately 274 events/manufacturing facility/workday. For disposal, it was conservatively assum ed that 100 units are disposed during an 8
-hour work day nationwide

. The maximum time weighted average (TWA) exposure was estimated for each exposure scenario, and this value compared to the Workplace Guidance Levels (WGLs) for propane and the potential impurities in the substitute

. The modeling results indicate that the short

- term (15

- minute and 30

- minute) and long

term (8

-hour) worker exposure concentrations are at a maximum, about 50 percent of the WGLs. Table 7 displays the maximum estimated 15

- minute TWA occupational exposure level s of propane and the potential impurities in the substitute . Even these maximum estimated short

- term occupational level s are significantly lower than the 8

-hour or 10
-hour long

- term WGL s , and therefore occupational expo sure to propane and the potential impurities is not considered a toxicity threat. Table 7 . Occupational Risk Assessment

Maximum 15 - minute TWA Occupational Exposure Levels (ppm) Workplace

Guidance Levels (ppm) a Workplace

Guidance Levels Time Period
Sub stitute Propane 502 1000 10
- hour TWA b Potential Impurities Ethane 0.9 NA NA Propylene 0.2 NA NA n - Butane 0.5 800 10
- hour TWA Sulphur 5.4 x 10
- 4 NA NA NA = Not Available a. See Table 5 for more information. b. The WGL for Propane is set as a 1000 pp m 8
- hr TWA by OSHA and a 10
- hr TWA by NIOSH. 6.3 END - USE EXPOSURE This section presents estimates of potential store employee and customer exposures to propane in ice cream cabinets

. An exposure analysis was performed to examine potential catastrophic release of the

8 ICF International maintains the Vintaging Model for EPA in order to simulate the aggregate impacts of the ODS phaseout on the use and emissions of various fluorocarbons and their substitutes over a period of several years across more than 40 differe nt applications. The model tracks the use and emissions of various compounds for the annual vintages of new equipment that ente r service in each end

- use. The vintage of each type of equipment determines such factors as leak rate, charge size, number of units in operation, and the initial ODS substance that the equipment contained. 9 During disposal it is assumed that only 90 percent of the refrigerant charge remains in the unit. 10 This number conservatively assumes that all Unilever cabinets in North America (a figure provided in the SNAP Submission) are in the US and that all will be replaced with R290 cabinets by 2010. This number of cabinets was divided by the number of predicted new small retail refrigeration units produced in 2010, from the Vint aging Model.8 May 26, 2009 substitute in a small storage room (as in Sections 4 and 5 ) under a reasonable “worst

- case” scenario . The analysis was undertaken to determine the 15

- and 30

- minute TWA exposure s for the substitute , which were then compared to the standard toxicity limits presented in Table 5 to assess the risk to consumers. However, the TWA values are fairly conservative as the analysis does not consider opened windows , fans operating, conditioned airflow (either heated or cooled) and other variables that would reduce the levels to which individuals would be exposed. The model involves a refrigerant leak from an ice cream cabinet into an enclosed storage room of volume 42 m3 (1,483 ft 3 )

. The model assume s that the individual is present at the start of the leak and the individual remains in the room while the refrigerant is released. It is also assumed that horizontal stratification causes most of the refrigerant to settle in higher concentrations closer to the ground. In order to simulate the horizontal concentration gradient that will occur because of the weight differential between the refrigerant and air, it is assumed that 95 percent of the leaked refrigerant mixes evenly into the bottom 0.4 meter of the room, and the rest of the refrigerant mixes evenly in the remaining volume (Kataoka 1999). Exposure concentrations were calculated using the box model described in the Background Document, which was adapted to estimate concentrations on a minute

-by

- minute basis. In the analysis, the full charge of the unit is assumed to be emitted over the course of one minute and the model conservatively assumes 2.5 air exchanges occur per hour. The highest expected levels of exp osure at the end

-use based on this analysis occur in the lower stratum of the room. The results of the assessment are presented in Table 8
. Table 8 . End - Use Exposure Assessment

15 - minute TWA Exposure (ppm) 30 - minute TWA

Exposure (ppm) Substitute Propa ne 10,41 4 7,96 3

Potential Impurities Ethane 19 1 5 Propylene 3.4 2. 6 n - Butane 11 8.6 Sulphur 0.01 0.00 9 TWA = Time Weighted Average While the IDLH for propane is 2,100 ppm, NIOSH (1996) notes that " b ased on acute inhalation toxicity data in humans (A CGIH 1991; Braker 1980), a value much greater than 10,000 ppm would have been appropriate. However, the revised IDLH for propane is 2,100 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 2.1%)." Therefore, it is believed that even under the very conservative assumptions used in this model, exposures to propane should not pose a toxicity threat. Steps to protect against fire or explosion in the space should be taken, as detailed in Section 4 . Exposure to the minute quantities of the impurities detailed in Table 8 is also not expected to pose a toxicity threat, given the low toxicity of these substances. Should catastrophic release from a cabinet located in the main ar ea of a store occur, exposure levels are not expected to pose a toxicity threat as the room volumes in the store would be larger than those used in this model

. 11 Thus, exposure concentrations would be even lower in the main area of the store.

11 An Armines (2008) study presents data from site visits to California convenience stores, “minimarkets” and supermarkets during which the minimum store area encountered was 100 m 2 . Assuming a 3 m ceiling height (as in the scenarios used in this risk screen), this is equal to a volume of 300 m3 , or more than seven times the volume of the store room used in this analysis.9 May 26, 2009 6.4 GENERAL P OPULATION EXPOSURE In the SNAP Background document for refrigerants (EPA 1994) , the RfC value for propane is 0.9 m/m3

. We compared this RfC to estimated factory releases and on

- site releases. This gives a ratio of exposure concentration to RfC that varie s between 1
. 9 x 10 - 4 to 3.5 x 10 - 1 , depending on the type of release scenario. 12 Ratios of exposure concentration to RfC for the substitute’s impurities (for which RfCs are available) were even lower. Since the exposure concentrations for the substance s a re lower than the RfC value s , the substitute is not expected to pose a toxicity threat to the general population. 

### 7. VOLATILE ORGANIC COMPOUND (VOC) ASSESSMENT Propane ha s not been exempt ed as a VOC under the CAA ( 40 CFR 51.000) . However, through regulations and standard industry practices, VOC emissions should be controlled. Chapter 8 of the Background Document shows that potential emissions of VOCs from all substitutes for all end uses in the refrigeration and air conditioning sector are likely to be insignificant relative to VOCs from all other sources (i.e., other industries, mobile sources, and biogenic sources ). Additional analysis shows that even if all ice cream cabinets produced by Unilever /Ben and Jerry’s in one year 13 were to leak their entire charge over the course of the year (extremely unlikely), the resulting annual VOC emissions would be only about 8.5 x10 - 5 percent of all annual anthropogenic VOC emissions. 14 As these emissions of propane are several orders of magnitude less than other anthropo genic emissions, the environmental impacts of these VOCs are not considered a threat. 

### 8. REFERENCES ACGIH. 1991. Propane. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 1286
- 1287. Armines. 2008. Inventory of Direct and Indirect GHG Emissions from Stationary Air Conditioning and Refrigeration Sources, with Special Emphasis on Retail Food Refrigeration and Unitary Air Conditioning. P rovisional Final Report. June 2008. Available at: < http://www.arb.ca.gov/cc/commref/armines_report_03_625.pdf>. Ben and Jerry’s/Unilever SNAP Submission. 2008. Significant New Alternatives Policy Program Submission to the United States Environmental Pro tection Agency, October 2008. Braker W, Mossman AL. 1980. Matheson gas data book. 6th ed. Secaucus, NJ: Matheson Gas Products, pp. 615 623. EPA 2008. Volatile Organic Compounds

– National Summary of VOC Emissions. Last updated 21 October 2008. Accesse d 4 March 2009. Available at <http://www.epa.gov/air/emissions/voc.htm>. 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.

12 Release scenarios include factory and on

- site releases, with and without recycling of the refrigerant. 13 Conservativel y assuming that all Unilever cabinets in North America (a figure provided in the SNAP Submission) are in the US and that all will be replaced with R290 cabinets. 14 This figure was calculated using 2002 annual VOC emissions data from EPA (2008)

.10 May 26, 2009 ICF
. 1997. Physiological Effects of Alternative Fire Protection Agents

- Hypoxic Atmospheres Conference. Stephanie Skaggs prepared the proceedings of the conference held May 22, 1997 in New London , CT. Kataoka. 1999. “Allowable Charge Limit of Flammable Refrigerants and Ventilation Requirements.” Draft Proposal. O. Kataoka/Daikin/Japan, June, 1999. NFPA. 2008. NFPA 58: Liquefied Petroleum Gas Code. National Fire Protection Agency. NI OSH. 1996. Propane: IDLH Documentation. August 1996. Accessed 17 Feburary 2009. Available online at: < http://www.cdc.gov/niosh/idlh/74986.html>. Sheldon, L.S., et al. 1989. "An Investigation of Infiltration and Indoor Air Quality." New York State Energy Research & Development Authority, Report 90

- 11. Wuebbles 2003. Personal communication with Don Wuebbles. E

- mail. July 21, 2003.