March 28, 2016 – Final 1 

## Significant New Alternatives Policy Program Refrigeration and Air Conditioning Sector

Risk Screen on Substitutes in Water Coolers

Substitute: Propane (R-290)

This risk screen is restricted to self-contained wa ter coolers meeting the requirements of UL 399.

This risk screen does not contain Clean Air Act (CA A) Confidential Business Information (CBI) and, therefore, may be disclosed to the public.



### 1. INTRODUCTION
Ozone-depleting substances (ODS) are being phased o ut of production in response to a series of diploma tic and legislative efforts that have taken place over the past two decades, including the Montreal Protoc ol 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 unacceptab le substitutes for ODS in specific end-uses based o n assessment of their health and environmental impact s. 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 pose d by the substitute in specific applications. EPA has already screened a large number of substitutes in m any end-uses and applications within all of the maj or ODS-using sectors including: refrigeration and air conditioning; solvent cleaning; foam blowing; aeros ols; fire suppression; adhesives, coatings and inks; and sterilization. The results of these risk screens a re presented in a series of Background Documents that are available in EPA's docket. The purpose of this risk screen is to supplement EP A’s Background Document on the refrigeration and ai r conditioning sector (EPA 1994) (hereinafter referre d to as the Background Document). This risk screen evaluates the potential use of propane (R-290) as a substitute in the drinking water cooler end-use. T able 1 presents the composition of the proposed substitute

.

Table 1. Composition of Propane and Potential Impu rities

Constituent Chemical Formula CAS Number Concentration (Weight Percent) a Propane (R

- 290) C 3 H 8 74

- 98

- 6 > 99. 7 % Potential Impurities (Maximum Concentration)

Ethane C 6 H 14 74-84-0 <0.17% Propylene C 3 H 6 115

- 07

- 1 < 0.03% n-Butane C 4 H 10 106-97-8 <0.1% Sulfur S 7704

- 34

- 9 < 0.001% Water H 2 O 7732-18-5 <0.0012%

Section 2 summarizes the results of the risk screen for the proposed substitute in Table 1. The remai nder of the risk screen is organized into the following sections:

• Section 3: Atmospheric AssessmentMarch 28, 2016 – Final 2 • Section 4: Volatile Organic Compound Assessment

• Section 5: Discussion of End-Use Scenario Modeled

• Section 6: Potential Health Effects

• Section 7: Flammability Assessment

• Section 8: Asphyxiation Assessment

• Section 9: End-Use Exposure Assessment

• Section 10: Occupational Exposure Assessment

• Section 11: General Population Exposure Assessment

• Section 12: References



### 2. SUMMARY OF RESULTS
Propane is recommended for SNAP approval for self-c ontained water coolers that comply with Underwriters Laboratory (UL) Standard 399: Drinking Water Coolers. EPA's risk screen indicates that th e use of the proposed substitute will be less harmful to the atmosphere than the continued use of ODS an d other commonly used refrigerants, as it is less har mful to the ozone layer, has lower climate impact, and a shorter atmospheric lifetime (ALT). Propane is regulated as a volatile organic compound (VOC) under CAA regulations (40 CFR 51.100(s)). Based on analysis potential impacts of hydrocarbon refrigerant emissions on ground-level ozone concentrations, VOCs from the use of propane are no t anticipated to result in greater impacts on local air quality in the United States than other available o ptions. It is expected that the manufacturer’s safe ty data sheet (SDS) for propane and good manufacturing prac tices will be adhered to during handling or use of propane. Additionally, it is expected that the appr opriate safety and personal protective equipment (P PE) (e.g., protective gloves, tightly sealed goggles, p rotective work clothing, and suitable respiratory p rotection in case of leakage or insufficient ventilation) con sistent with Occupational Safety and Health Administration (OSHA) guidelines will be used durin g manufacture, installation and servicing, and disposal of water coolers using propane. Because wa ter coolers are to be installed in locations with adequate space and/or ventilation in accordance wit h EPA recommendations and the equipment maintenance manuals for propane, significant flamma bility, asphyxiation, or toxicity risk to consumers is unlikely. Additional safeguards, including the refrigerant co ncentration limit (RCL) for propane, are provided i n industry standards such as American Society of Heat ing, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standards 15, 1 34, 2 and 62 3 and UL Standard 399: Drinking Water Coolers. 4

1 Safety Standard for Refrigeration Systems ASHRAE St andard 15 establishes safeguards for life, limb, he alth, and property and prescribes safety requirements.

2 Designation and Safety Classification of Refrigeran ts ASHRAE Standard 34 is establishes a uniform syst em for assigning reference numbers, safety classifications, and refr igerant concentration limits to refrigerants. Safe ty classifications based on toxicity and flammability data are included.

3 Ventilation for Acceptable Indoor Air Quality ASHRA E Standard 62 establishes minimum ventilation rates and other measures intended to provide indoor air quality that is acce ptable to human occupants and that minimizes advers e health effects.

4 UL 399 Standard for Safety: Drinking Water Coolers establishes safety requirements for self-contained drinking water coolers employing hermetic refrigerant motor-compressors or thermoelectric water chilling systems and designed for connection to alternating-current circuits rated not greater than 600 volts (ANSI/UL 2013).March 28, 2016 – Final 3 

### 3. ATMOSPHERIC ASSESSMENT
This section presents an assessment of the potentia l risks to atmospheric integrity posed by the use o f propane in water coolers. The ozone depletion poten tial (ODP), global warming potential (GWP), and ALT of the proposed substitute are presented in

Table 2. The proposed substitute is substantially less harmf ul to the ozone layer, has lower climate impact, an d a shorter ALT when compared to refrigerants such as C FC-12, R-502, and HCFC-22. In addition, propane also has lower climate impact and a shorter ALT tha n those predicted for other substitutes examined in the Background Document as well as the commonly utilize d refrigerant HFC-134a. Thus, EPA believes that the use of propane would result in substantially le ss harm to the climate and ozone layer than the con tinued use of ODS and other commonly used refrigerants. Table 2. Atmospheric Impacts of Propane Compared t o Other Refrigerants Used in Water Coolers
Refrigerant Ozone Depleting Potential (ODP) a Global Warming Potential (GWP) b Atmospheric Lifetime in Years (ALT) b Propane 0 b 3.3 0.03 a CFC

- 12 0.82 10,900 100 R

- 502 c 0. 2 4,650 NA d HCFC

- 22 0.13 1,810 12 a HFC

- 134a 0 1,430 14 NA – Not applicable

a World Meteorological Organization (WMO) 2010 Scient ific Assessment Report (2011)

b Intergovernmental Panel on Climate Change (IPCC) 4 th Assessment Report (Forster et al. 2007)

c R-502 is a blend consisting of HCFC-22 (49%) and CF C-115 (51%).

d Atmospheric lifetimes are not given for blends, be cause the components separate in the atmosphere. Th e ALT for HCFC-22 is 12 years and the ALT for CFC-115 is 1,700 years (IPCC 4 th Assessment Report [Forster et al. 2007]).



### 4. VOLATILE ORGANIC COMPOUND (VOC) ANALYSIS
Propane is regulated as a VOC under CAA regulations (40 CFR 51.100 [s]). Emissions of propane should be controlled according to CAA and other regulation s by adhering to standard industry practices. EPA prepared a separate analysis in 2014 5 and a follow-on analysis in 2016 6 to evaluate the potential impact of the use of hydrocarbon refrigerants on gr ound-level ozone concentrations in the United State s. These analyses estimated refrigerant emissions from refrigeration and air conditioning equipment, whic h were assumed to contain propylene, isobutane, and/o r propane 7 under different scenarios and compared their resulting relative increases in ozone concent rations against the National Ambient Air Quality Standard (NAAQS) for ozone of 70 ppb. 8 Under the most conservative scenario it was assume d that

5 Assessment of the Potential Impact of Hydrocarbon R efrigerants on Ground Level Ozone Concentrations (February 2014) [EPAHQ-OAR-2013-0748-0003]
6 Follow-on Assessment of the Potential Impact of Hydrocarbon Refrigerants on Ground Level Ozone Conc entrations (March 2016)

7 EPA uses the maximum incremental reactivity (MIR) o f ethane (0.28 g-O 3 /g-substance) as the threshold for determining whet her a compound has negligible reactivity. Propylene (MI R = 11.57), isobutane (MIR = 1.34), and propane (MI R 0.56) are all considered to be reactive compounds and are therefo re subject to VOC regulations.
8 On October 1, 2015, EPA strengthened the NAAQS for ground-level ozone to 70 ppb from 75 ppb, based on scientific evidence about ozone’s effects on public health and welfare (EPA 2015).March 28, 2016 – Final 4 propylene was used in all refrigeration and air con ditioning equipment. In more realistic scenarios, a ll three hydrocarbons (and/or blends thereof) were ass umed to be used in certain types of refrigeration a nd air conditioning equipment, depending on the propos ed use of each alternative under submissions receiv ed by the SNAP program at the time of the analysis. End-uses in the evaluation included a number of typ es of smaller, self-contained refrigeration and roo m air-conditioning units for which SNAP hydrocarbon a pplications have been received and/or UL Standards covering flammable refrigerants exist. 9 The hydrocarbon emissions from these scenarios wer e estimated based on EPA’s Vintaging Model, and their potential contributions to ozone concentrations were assesse d using EPA’s Community Multiscale Air Quality (CMAQ) model. 10
CMAQ modeling was performed for April through the e nd of September, as these months presented the largest releases of hydrocarbon refrigerant as well as weather conditions favorable for ozone formation. The ozone concentrations were estimated for the Atlanta, Houston, and Los Angeles regions, due to their distinctive geographic setting and chr onic high levels of ground-level ozone, and then sc aled for national emission estimates. The results of the CMAQ modeling indicated that und er the most conservative case which assumed that the most reactive hydrocarbon, propylene, was used in all refrigeration and air conditioning equipment

, there could be an incremental maximum increase of t he 8-hour average as high as 7.8 ppb ozone in 2040. By comparison, the most realistic scenario, in whic h a mixture of hydrocarbon refrigerants are used, refrigerant emissions could potentially increase th e maximum 8-hour average ground-level ozone by no more than 2.5 ppb in 2040 in Los Angeles, the city with the greatest ozone problem. This upper bound level of increase for the realisti c scenario is not likely, as most ozone nonattainme nt areas are not VOC-limited (i.e., the formation of o zone in these areas is not limited by VOC emissions , but by other compounds such as nitrogen oxides [NO x ]). In addition, the analysis assumed no use of VOC

exempt refrigerants which will also likely be used in refrigeration and air conditioning end-uses alon g with hydrocarbon refrigerants. Based on the results of t his analysis, VOC emissions from the use of propane in water coolers are not anticipated to contribute sig nificantly to ground level ozone concentrations in the United States.



### 5. DISCUSSION OF END-USE SCENARIOS MODELED
Propane has been proposed for the water coolers end -use. The modeled end-use scenarios assume a charge size of 60 grams for residential water coolers and a charge size of 135 grams for commercial water coo lers. The 60-gram charge size is consistent with UL Worki ng Group 2’s proposed revision to UL Standard 399: Drinking Water Coolers, which limits the charge siz e of drinking water cooler refrigeration equipment for ASHRAE classified A3 refrigerants to 60 grams (UL 2 015). The typical charge size of 135 grams was provided by the submitter. Although the submitter’s typical charge size does not comply with the propo sed revisions to UL Standard 399, a water cooler with a 135-gram charge size is modeled to assess the risk associated with the equipment submitted for SNAP ap proval, in addition to other water cooler units tha t are expected to enter the market if the proposed UL standard is finalized.

9 Water coolers were not included as an end-use in th e CMAQ modeling assessment. Because the incremental changes in groundlevel ozone were insignificant between all modeled refrigeration and air-conditioning equipment, use i n water coolers is not expected to significantly affect the estimated impa ct on ground-level ozone concentration.
10 VM version VM_IO file_v4.4_10.13.14 and CMAQ model version 5.0.2 were used in this analysis.March 28, 2016 – Final 5 Water coolers can be installed in a wide range of l ocations with varying room volumes (e.g., household kitchens, hotels, office buildings, and restaurants ). To represent reasonable worst-case scenarios for water coolers, it is assumed that a catastrophic leak of refrigerant occurs while a water cooler is installe d at a residential end-use (i.e., small household kitchen) or commercial end-use (i.e., restaurant kitchen). The analysis in this risk screen conservatively assumes that the water cooler is located in either a small household kitchen with an effective volume of 18 m 3 (640 ft 3 ) (i.e., excluding the space filled by cabinets, other kitchen equipment, etc.) and a height of 2.4 meters (7.8 feet), or a restaurant kitchen with an effective volume of 244 m 3 (8,620 ft 3 ) (i.e., excluding the space filled by the water co oler, shelving, other kitchen equipment, etc.) and a height of 2.4 meters (7.8 fe et).
Under these reasonable worst-case scenarios, the fu ll charge of the unit is assumed to be emitted over the course of one minute into the household kitchen wit h 2.3 air change(s) per hour (ACH) or a restaurant kitchen with 20 ACH. 11 A vertical concentration gradient is also assumed in the worst-case scenarios since propane is denser than air (specific gravity of pro pane relative to air is 1.52 [air = 1]) and will se ttle in higher concentrations closer to the ground. In orde r to simulate the vertical concentration gradient o f refrigerant following release, it is assumed that 9 5 percent of the leaked refrigerant mixes evenly in to the bottom 0.4 meters (1.3 feet) of the room, and the r est of the refrigerant mixes evenly in the remainin g volume (Kataoka 2000). Table 3 details the end-use modeling assumptions used throughout the risk scree n (i.e., in Sections 7, 8 and 9). Table 3. End-Use Scenario Model Assumptions

Parameter Assumptions Residential Commercial Room Household Kitchen Restaurant Kitchen Charge Size (g) 60 a 135 b Length of Release (minutes) 1 1 Room Size (volume

- m 3 ) 18 c (640 ft 3 ) 244 d ( 8,6 2 0 ft 3 ) Room Ventilation (air changes per hour) 2.3 c 20 e
Vertical Concentration Gradient Yes Yes

a UL 399 proposed maximum charge size for water coole rs using Class A3 refrigerants.

b Charge size indicated by the submitter (Blupura 201 5).

c Background Document (EPA 1994)

d Specific information was not available regarding th e volume of rooms utilizing commercial water cooler s, so a restaurant kitchen (assumed to be equal to the volume of a sma ll convenience store) was used in the model. The mi nimum convenience store size found during a California su rvey (Armines 2008) – 100 m 2 – was used for this scenario and an 8-foot ceiling was assumed.

e The typical ventilation rate for a commercial kitch en is 20 to 40 air changes per hour (McMullan 2014)

. EPA recognizes that water coolers may be placed in a variety of locations with different room sizes an d ventilation rates. When units are installed in smal ler, enclosed spaces, there is a higher risk for asphyxiation or exposure concerns. To address this variability in room volumes and charge sizes for installed water coolers, this risk screen incorpora tes threshold analyses in addition to the worst-cas e scenario modeling. The threshold analyses are perfo rmed in order to determine the room size and charge size requirements that ensure that the use of propa ne in water coolers does not present risk to end-us ers or servicing technicians.

11 The air exchange rate for a commercial (restaurant) kitchen is derived from the suggested sufficient a ir changes per hour in commercial kitchens of 20 and 40 air changes per ho ur (McMullan 2014).March 28, 2016 – Final 6 

### 6. POTENTIAL HEALTH EFFECTS
To assess potential health risks from exposure to t he proposed substitute in water coolers, EPA identi fied the relevant toxicity threshold values for comparis on to modeled exposure concentrations for different scenarios. According to ASHRAE Standard 34, propane is listed under safety group A3 with a RCL of 5,300 ppm (ASHRAE 2013a). ASHRAE 34 RCLs are intend ed to reduce the risks of acute toxicity, asphyxiation, and flammability hazards in normally occupied, enclosed spaces during refrigerant use an d protect end-users from the potential dangers of a c atastrophic leak from a refrigeration unit (ASHRAE 2013a). ASHRAE Standard 15 implements the aforement ioned standard, requiring that “the concentration of refrigerant in an enclosed space following a com plete discharge of a high-probability system shall not exceed the RCL” (ASHRAE 2013b). As such, this risk screen references the RCL for propane in addition to the LFL, hypoxia no observed adverse effect leve l (NOAEL) and exposure limits, as an additional, conservative limit to ensure that significant flamm ability, asphyxiation, and end-use exposure risks, respectively, do not occur. For the occupational exposure analysis, potential r isks from chronic and acute worker exposure were evaluated by comparing exposure concentrations with available occupational exposure limits. Potential risks of chronic worker exposure were evaluated usi ng workplace guidance levels (WGL). Risks from potential short-term consumer exposures were evalua ted by comparing exposure concentrations to emergency guidance levels (EGL). In the absence of an established short-term exposure limit (STEL), acute exposure guideline level (AEGL), or emergency response planning guideline (ERPG), potential short-term, end-use exposures were evaluated. Table 4 lists the relevant toxicity limits and RCL of pr opane and is followed by Table 5, which provides an expla nation of each toxicity limit. EPA’s approach for identifying or developing these values is discussed in Chapter 3 of the Background Document. Table 4. Exposure Limits of Propane

Component WGL

(Long-term Exposure) ppm EGL (Short-term Exposure) Ppm Refrigerant Concentration Limit (RCL) ppm Propane 1,000 a

(OSHA PEL/NIOSH REL) 10,000 b,c (10

- min AEGL

- 1) 6,900 c (30-min AEGL-1) 5,300 d
Potential Impurities
Ethane 1,000 e (ACGIH TLV) 3,000 f (30

- min ACGIH Excursion Limit) 2,900 g (15-min TEEL-1) 7,000 d
Propylene 500 e (ACGIH TLV) 1,500 f (30-min ACGIH Excursion Limit) 1,000 d n-Butane 1,000 e (ACGIH TLV) 6,900 h (30-min AEGL-1) 4,000 d An explanation of each exposure limit and exposure- limit related terminology is described in Table 5.

a OSHA PEL available at: http://www.cdc.gov/Niosh/np g/npgd0524.html

b An IDLH of 2,100 ppm has been established for propa ne. However, NIOSH (1996) states that "[b]ased on acute inhalation toxicity data in humans (ACGIH 1991; Braker 1980), a value much grea ter than 10,000 ppm would have been appropriate. Ho wever, the revised IDLH for propane is 2,100 ppm based strictly on safety consi derations (i.e., being 10% of the lower explosive l imit of 2.1%)." Therefore, as this IDLH value is based on flammability concerns and not tox icity concerns, it is not used in the evaluation of toxicity risks in this risk screen.

c AEGL-1 available at: http://www.epa.gov/opptintr/a egl/pubs/results96.htm

d ASHRAE (2013b)

e ACGIH TLV for aliphatic hydrocarbon gases: alkane (C 1 - C 4 ) is 1,000 ppm TWA (ACGIH 2012)

f Calculated as three times the TLV-TWA (ACGIH 2004).

g Department of Energy (DOE) (2008)

h AEGL-1 available at: http://www.epa.gov/oppt/aegl/p ubs/rest102.htmMarch 28, 2016 – Final 7 Table 5. Explanation of Exposure Limit-Related Term inology a Organization Definition OSHA Occupational Safety and Health Administration NIOSH National Institute for Occupational Safety and Heal th ACGIH American Conference of Governmental Industrial Hygi enists AIHA American Industrial Hygiene Association OARS Occupational Alliance for Risk Science Exposure Limit Definition Explanation Short

- Term Exposure RCL Refrigerant Concentration

Limit The RCL for a refrigerant is intended to reduce the risks of acute toxicity, asphyxiation, and flammability hazards in normally occupied, enclosed spaces. The RCL for each refrigerant is the lowest of the Acute-Toxicity Exposure Limit (ATEL), Oxygen Deprivation Limit (OD L), and Flammable Concentration Limit (FCL). Determination assumes fu ll vaporization with no removal by ventilation, dissolution, reaction, o r decomposition and complete mixing of refrigerant in the space to whic h it is released. STEL Short

- Term Exposure Limit A 15

- minute TWA exposure that should not be exceeded dur ing a workday, even if the 8-hour TWA is within the TLV–T WA, set by ACGIH.

AEGL b,c Acute Exposure Guideline

Level 1 AEGL

- 1 is the airborne concentration (expressed as ppm or mg/m 3 ) of a substance above which it is predicted that the gene ral population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic nonsensory effe cts. However, the effects are not disabling and are transient and rev ersible upon cessation of exposure. Acute Exposure Guideline Level 2 AEGL

- 2 is the airborne concentration (expressed as ppm o r mg/m 3 ) of a substance above which it is predicted that the gene ral population, including susceptible individuals, could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape. Acute Exp osure Guideline Level 3 AEGL

- 3 is the airborne concentration (expressed as ppm o r mg/m 3 ) of a substance above which it is predicted that the gene ral population, including susceptible individuals, could experience life-threatening health effects or death.

TEEL d Temporary Emergency

Exposure Limit 1 TEEL

- 1 is the maximum concentration in air below which i t is believed nearly all individuals could be exposed without exp eriencing other than mild transient adverse health effects or perceiving a clearly defined, objectionable odor. Temporary Emergency Exposure Limit 2 TEEL

- 2 is the maximum concentration in air below which i t is believed nearly all individuals could be exposed without exp eriencing or developing irreversible or other serious health eff ects or symptoms that could impair their abilities to take protective act ion. Temporary Emergency Exposure Limit 3 TEEL

- 3 is the maximum concentration in air below which i t is believed nearly all individuals could be exposed without exp eriencing or developing life-threatening health effects. Long

- Term Exposure PEL Permissible Exposure Limit This is an 8

- hour TWA exposure limit set by OSHA. REL e Recommended Exposure

Limit This is an 8

- hour TWA recommended by NIOSH.

TLV

- TWA Threshold Limit Value

– Time

Weighted Average The TWA concentration for a conventional 8

- hour workday and a 40

- hour workweek, to which it is believed that nearly all workers may beMarch 28, 2016 – Final 8 repeatedly exposed, day after day, for a working li fetime without adverse effect according to ACGIH.

a All information in this table is taken from EPA (19 94) except where otherwise noted.
b EPA (2012)

c Applicable to emergency exposure periods ranging fr om 10 minutes to 8 hours.

d DOE (2008)

e NIOSH (2015) According to the SDS, exposure to propane may be ha zardous if inhalation, skin contact, or eye contact with the proposed substitute occurs. The most likel y pathway of exposure is through inhalation. Propan e can cause symptoms of asphyxiation when present in concentrations high enough to significantly lower oxygen concentrations below 19.5 percent by volume, such as headaches, ringing in ears, dizziness, drowsiness, nausea, vomiting, depression of all sen ses, and also unconsciousness. Under some circumstances of over-exposure (i.e., oxygen levels fall below 6 percent by volume), death may occur. In addition, at high concentrations, propane can act a s a narcotic and cause central nervous system depression, including dizziness, drowsiness, and he adaches. If propane is inhaled, person(s) should be immediat ely removed from the contaminated space and exposed to fresh air. In accordance with the SDS, EPA furth er recommends that if breathing is difficult or irr egular, person(s) should be given oxygen, provided a qualif ied operator is present, and medical attention be sought. Exposures of propane to the skin may cause frostbite. In the case of dermal exposure, the SDS for propane recommends that person(s) immediately wash the affected area with water and remove all contaminated clothing; if frostbite occurs, 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, and seek medical attentio n immediately. Exposures of propane to the eyes could cause eye irritation. In case of ocular exposure, the SDS for propane recommends that person(s) immediate ly flush the eyes, including under the eyelids, wit h copious amounts of water for 15 minutes. EPA’s review of the human health impacts of this pr oposed substitute is contained in the public docket for this decision. The potential health effects of propane can be mini mized by following the exposure guidelines and ventilation and PPE recommendations outlined in the SDS for propane and this risk scree n.



### 7. FLAMMABILITY ASSESSMENT
ASHRAE Standard 34 classifies propane as a Class A3 refrigerant. Propane is flammable when its concentration in air is in the range of 2.1 percent to 9.5 percent by volume (21,000 ppm to 95,000 ppm ). In the presence of an ignition source (e.g., static electricity or a cigarette), an explosion or a fir e could occur if the concentration of propane were to excee d the LFL of 21,000 ppm. The remainder of this sect ion addresses flammability risks and summarizes the rec ommended measures to ensure safe handling and use of the refrigerant during manufacture, servicing, a nd end-use. 7.1 Flammability Risks at Equipment Manufacture Release of or exposure to propane may be possible a t the charging and sealing steps on the production line at the manufacturing site. It is therefore importan t that all relevant standards be followed during th e manufacture of water cooler refrigeration units. If the manufacture of water cooler units charged with propane occurs in the United States, EPA recommends that engineering controls should include normal and local ventilation (e.g., chemical hoods) for st andard manufacturing procedures so workers can avoi d physical contact with the refrigerant and to limit emissions. In general, use of appropriate PPE consi stent with OSHA guidelines is recommended, such as splash goggles, mechanically-resistant gloves whenMarch 28, 2016 – Final 9 handling cylinders, chemically-resistant gloves (e. g., butyl rubber, chlorinated polyethylene, or neop rene) when handling the gas mixture, and protective cloth ing. All propane storage and transport equipment should be installed with safety devices that minimize the likelihood of catastrophic releases. For example, t he National Fire Protection Association (NFPA) 58 Liquefied Petroleum Gas Code (NFPA 2007) for liquef ied propane requires the use of overfill protection devices (OPD) on cylinders to minimize the likeliho od of leaks. The NPFA 58 Code also contains propane storage and transportation requirements/guidelines. It is expected that refrigerants be properly store d and caution used within manufacturing facilities to min imize explosion risk and that workers adhere to the requirements set by OSHA under 29 CFR 1910. OSHA re quirements include proper ventilation and storage practices within manufacturing facilities t o prevent fire and explosion. Good manufacturing practices should be adhered to during the manufactu re of equipment containing propane, e.g., using pro per ventilation. 7.2 Flammability Risk at Servicing and End-Use The risk of flammability during servicing and end-u se for the reasonable worst-case scenarios (see Sec tion 5) were investigated for propane. Both servicing an d end-use of propane water coolers are expected to take place in the same space (i.e., the installation and use location). In order to determine the potential flammability risks during servicing or end-use in c ase of a catastrophic release of refrigerant, model ed concentrations of propane immediately following the release of refrigerant were compared with the LFL for propane. The results of the flammability assessment are pres ented in Table 6.

Table 6 . Flammability Assessment a

Water Cooler Application Scenario Charge Size (g) Effective Room Size (m 3 ) Maximum

Instantaneous Concentration (ppm) b,c Residential Reasonable Worst-Case Scenario 1 60 18 (640 ft 3 ) 10,290 Commercial Reasonable Worst-Case Scenario 2 135 244 (8,620 ft 3 ) 1,710 Residential Threshold Analysis 1a: Charge Size 120 18 (640 ft 3 ) 21,000 Commercial Threshold Analysis 1b: Charge Size 1,660 244 (8,620 ft 3 ) 21,000 Residential Threshold Analysis 2a: Room Size 60 9 (320 ft 3 ) 21,000 Commercial Threshold Analysis 2b: Room Size 135 20 (710 ft 3 ) 21,000
Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with a cceptable exposure levels given various modeling as sumption options.

b LFL of propane is 21,000 ppm.

c Values provided in this column refer to the concent ration in the lower 0.4 meters of the room, which p resents the most conservative risk as 95 percent of the leaked refrigerant is present in this space. As demonstrated in Table 6, the maximum instantaneo us concentration in the lower 0.4 meters of the roo m does not exceed the LFL for propane in either worst -case scenario. Furthermore, the maximum instantaneous concentration in the upper portion in the room is much lower, as only 5 percent of the l eaked refrigerant is present in this area, which has grea ter volume than the lower 0.4 meters. As a result, release of a 60-gram or 135-gram unit does not present a si gnificant flammability risk in the reasonable worst -case scenarios for propane in water coolers. For the flammability analysis shown in Table 6, the conditions at which a flammability concern would exist (i.e., when the maximum instantaneous concent ration in the lower 0.4 meters of the room equals t he LFL for propane) were also determined.March 28, 2016 – Final 10 • In a household kitchen of 18 m 3 (640 ft 3 ), as shown under Threshold Analysis 1a, the charge size of the propane water cooler would have to be at lea st 120 grams for flammability to be a concern, which is two times greater than the maximum charge size proposed by UL 399 (i.e., 60 grams).

• As shown under Threshold Analysis 1b, the charge si ze of the commercial propane water cooler unit in a 244 m 3 room would have to be at least 1,660 grams for fla mmability to be a concern, which is approximately twelve times greater than th e charge size indicated by the submitter (i.e., 135 grams).

• In order for flammability risk to occur from the re lease of a 60-gram water cooler, the volume of the room would have to be approximately 9 m 3 (320 ft 3 ), or approximately half the modeled household kitchen volume (see Threshold Analysis 2a ).

• Using the charge size of 135 grams for commercial w ater coolers, as shown under Threshold Analysis 2b, the volume of the room would have to b e approximately 20 m 3 (710 ft 3 ), or approximately twelve times smaller than the modeled restaurant kitchen volume for flammability to be of concern (see Threshold Analysis 2b). According to the results of this flammability analy sis, the risk of fire is minimal if a water cooler is installed in a room with volumes in accordance with standards and regulations and if it meets the prop osed requirements of UL 399, including a charge size of 60 grams. As kitchens can be smaller than those modeled in this assessment and because persons or furniture in the room may re duce the effective volume of the space, refrigeration units containing propan e should not be installed in enclosed areas with ef fective volumes less than indicated by relevant safety stan dards (e.g., ASHRAE 15, 34, and UL 399) unless additional steps are taken to protect against a fla mmability risk (e.g., higher ventilation rates). Th e submitter also indicates propane water coolers will contain a VOC detection device that triggers an automatic shut-off valve when refrigerant leaks at 25 percent of the LFL for propane are detected (Blu Pura 2015). According to ASHRAE Standard 34, the RCL for propan e (9.5 g/m 3 of propane or 5,300 ppm by volume) should not be exceeded in any room that contains a propane refrigeration unit. Although the RCL for propane is less conservative than the anticipated r elease amount of propane under the modeled worst-ca se scenario for a 60-gram unit (i.e., 60 grams in a 18 m 3 space, or 3.3 g/m 3 ), the RCL is calculated assuming that refrigerant is evenly mixed in the space, wher eas this analysis assumes a vertical concentration gradient occurs due to the higher density of propan e than that of air (propane = 1.52, air = 1). End-u sers, therefore, should ensure that propane refrigeration units are installed in locations with areas that a re consistent with manufacturer recommendations and th e guidelines of relevant safety standards (e.g., ASHRAE 15 and 34 and UL 399). EPA recommends that warning labels are present on t he equipment indicating that flammable refrigerants in use as well as notifying the user to read the eq uipment use instructions that provide safety guidel ines for handling propane. These guidelines should be follow ed to mitigate flammability risk. The installation of leak prevention devices would further protect again st the very limited risk of explosion. During servi cing operations, EPA recommends that the ventilation req uirements outlined in the SDS for propane are followed through the use of fans or other mechanica l ventilation devices and that portable refrigerant detectors are used to alert technicians to the pres ence of flammable gases in order to mitigate the ri sk of fire or explosion during catastrophic leak. It is a lso important that only properly trained and certif ied technicians handle propane. As a further precaution , certification requirements and training programs for technicians that handle propane should be developed using these guidelines.March 28, 2016 – Final 11 

### 8. ASPHYXIATION ASSESSMENT
The risk of asphyxiation for the reasonable worst-c ase scenarios described in Section 5 were investiga ted for propane. In this section, risk of asphyxiation is assessed in three ways: 1) Modeling the oxygen concentration under the char ge size and room size specified in the worstcase scenario, 2) performing a threshold analysis of minimum charg e size at which an asphyxiation risk could occur in the room size specified in the worst-case scenario (i.e., charge sizes greater than this are expected to cause an asphyxiation risk), and 3) performing a threshold analysis of the maximum r oom size at which an asphyxiation risk could occur with the charge size specified in the worst-c ase scenario (i.e., room sizes smaller than this are expected to cause an asphyxiation risk). This analysis does not consider ventilation or cond itions that are likely to occur that would increase oxygen levels to which individuals would be exposed , such as open doors or windows, fans operating, conditioned airflow (either heated or cooled), or e ven openings at the bottom of doors that allow air to flow in and out. As specified in Section 5, the rea sonable worst-case scenarios assume a vertical concentration gradient. If the proposed substitute passes the screening analysis with these restrictiv e assumptions in place, it can be reasonably assumed that no risks of asphyxiation will be present under realworld conditions. The results of the asphyxiation a ssessment are summarized in Table 7 below. Table 7. Asphyxiation Assessment a,b

Scenario Charge Size (g) Effective Room Size (m 3 ) Percent Oxygen Concentration in Lower 0.4 Meters Reasonable Worst-Case Scenario 1 60 18 (640 ft 3 ) 21% Reasonable Worst-Case Scenario 2 135 244 (8,620 ft 3 ) 21% Threshold Analysis 1a: Charge Size 2,280 18 (640 ft 3 ) 12% Threshold Analysis 1b: Charge Size 30,790 244 (8,620 ft 3 ) 12% Threshold Analysis 2a: Room Size 60 0.48 (17 ft 3 ) 12% Threshold Analysis 2b: Room Size 135 1.1 (39 ft 3 ) 12%
Bold font indicates modeling results.

a Cells highlighted in green are the scenarios in wh ich the charge and room sizes evaluated in this ris k screen are acceptable according to the threshold analysis or the scenarios with acceptable oxygen concentrations, given various modeling ass umption options.

b The typical concentration of oxygen in air is cons idered to be 21 percent (Mackenzie & Mackenzie 1995 ). In order for a risk of asphyxiation to occur, the n ormal concentration of oxygen in air (21 percent) m ust be reduced to 12 percent. 12 Based on the reasonable worst-case scenario modeli ng, a release of propane from water coolers has an insignificant impact on the co ncentration of oxygen in the air and therefore does not present a significant risk of asphyxiation. This mo deling does not take into account any ventilation w hich is likely to occur, as mentioned above, so the actu al asphyxiation risk to person(s) is likely to be e ven smaller than modeled. For the asphyxiation threshold analyses shown in Ta ble 7, the conditions at which an asphyxiation conc ern would exist were determined.

12 Twelve percent oxygen in air is the NOAEL for hypo xia (ICF 1997).March 28, 2016 – Final 12 • Within a household kitchen of 18 m 3 (640 ft 3 ), as shown under Threshold Analysis 1a, the charge size of the propane water cooler would have to be a t least 2,280 grams for asphyxiation to be a concern, which is thirty-eight times greater than t he charge size proposed by UL (i.e., 60 grams).

• As shown under Threshold Analysis 1b, the charge si ze of the commercial propane water cooler unit in a 244 m 3 room would have to be at least 30,790 grams for as phyxiation to be a concern, which is approximately 230 times greater than the c harge size indicated by the submitter (i.e., 135 grams).

• In order for a risk of asphyxiation to occur from t he release of a 60-gram water cooler, the volume of the room would have to be approximately 0.48 m 3 (17 ft 3 ), or approximately thirty-eight times smaller than the modeled household kitchen volume ( see Threshold Analysis 2a).

• Using the larger charge size of 135 grams for water coolers, as shown under Threshold Analysis 2b, the volume of the room would have to be approxi mately 1.1 m 3 (38 ft 3 ), or approximately 220 times smaller than the modeled restaurant kitchen v olume for asphyxiation to be of concern. Based on the worst-case modeling results and thresh old analysis, EPA does not believe that the use of propane water coolers poses a significant risk of a sphyxiation or impaired coordination to personnel, provided systems are installed in appropriate space s according to guidelines from the manufacturer and the SDS for propane.



### 9. END-USE EXPOSURE ASSESSMENT
This section presents estimates of potential end-us er exposures to propane in the event of a catastrop hic release from the proposed substitute’s use in water coolers. An end-use exposure analysis was performe d to examine potential catastrophic releases of propa ne under the reasonable worst-case scenarios outlin ed in Section 5. For the end-use exposure assessment scenario, 30-mi nute TWA exposures for the proposed substitute were calculated using the box model described in the Bac kground Document, which was adapted to estimate concentrations on a minute-by-minute basis. Estimat es for acute/short-term end-use exposures resulting from catastrophic leakage of refrigerant from a wat er cooler were examined. As discussed in Section 5, the full charge of the unit is assumed to be emitted ov er the course of 1 minute. The analysis was underta ken to determine the 30-minute TWA exposures of propane , which were then compared to the standard toxicity limits presented in Table 4 to assess the risk to e nd-users. The estimated TWA values are fairly conservative as the analysis reflects minimal airfl ow (i.e., natural ventilation), but does not consid er mechanical ventilation such as fans, conditioned ai rflow (either heated or cooled) and other variables that would reduce the levels to which individuals would be exposed. Table 8 displays the estimated exposure s to propane at end-use.March 28, 2016 – Final 13 Table 8. End-Use Exposure Assessment for Propane a

Scenario Charge

Size (g) Room Size

(m 3 ) Vertical

Concentration Gradient Ventilation

Rate (ACH) 30

- min TWA End

Use Exposure (ppm) b Reasonable Worst-Case Scenario 1 60 18 (640 ft 3 ) Yes 2.3 6,190 Reasonable Worst

- Case Scenario 2 135 244 (8,620 ft 3 ) Yes 20 170 Threshold Analysis 1 a : Charge Size 67 18 (640 ft 3 )

Yes 2.3
6,900 Threshold Analysis 1b: Charge Size 5,430 244 (8,620 ft 3 ) 20 Threshold Analysis: 2a Room Size 60 16 (5 65 ft 3 ) 2.3 Threshold Analysis 2b: Room Size 135 6 ( 2 1 0 ft 3 ) 20 Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with acceptable exposure levels given various modeling a ssumption options.

b 30-minute AEGL-1; see Table 4 for more information.

Under the reasonable worst-case scenarios described in Section 5 for water coolers, the catastrophic r elease of both a 60-gram and 135-gram water cooler unit we re modeled. The anticipated 30-minute TWA exposures of propane do not exceed its 30-minute AE GL (i.e., 6,900 ppm) for all scenarios. All of the exposure estimates in Table 8, with the exception o f Reasonable Worst-Case Scenario 1, are lower than the RCL of 5,300 ppm for propane. Although the exposure estimate for Reasonable Worst-Case Scenario 1 exceeds the RCL (i.e., 5,300 ppm) (see Table 8), th is scenario assumes a vertical concentration gradie nt and the RCL is calculated assuming that refrigerant is evenly mixed in the space. Therefore, the estim ated exposure represents concentrations of leaked refrig erant in the bottom 0.4 meter (1.3 feet) of the roo m, accounting for 95 percent of the refrigerant charge in this lower portion of the room. The probability that an individual would be present in this lower portio n (e.g., prone or supine on the floor or a crawling infant) in the event of the catastrophic release of refrige rant is low. In addition, these exposure estimates were derived using conservative assumptions (e.g., minimum room volume, low ventilation rate) that do not necessari ly reflect the actual room attributes where propane water coolers will be installed. Specifically, Reasonable Worst-Case Scenarios 1 models a 60-gram water cool er in a fairly small kitchen size that would likely co ntain a water cooler with a smaller charge size. Furthermore, household and commercial kitchen space s are often connected to other rooms (e.g., an eat- in space, hallway) through open pathways or swinging d oors, which would increase the effective volume of the space into which a refrigerant would be release d, thereby reducing the likelihood that end-users w ould be exposed to modeled concentrations. To further analyze potential risks of exposure duri ng end-use, threshold analyses were conducted to determine the room size and charge size requirement s that ensure that the use of propane in these end- uses does not present risk to end-users or servicing tec hnicians. Based on these results, EPA recommends th at for a minimum room volume of 18 m 3 , the charge size is consistent with the proposed l imits in UL 399 and does not exceed 60 grams (see Threshold Analysis 1a in Table 8). The analysis also indicates a 60-gram refrigeration unit should not be installed in a roo m of effective volume less than 16 m 3 (530 ft 3 ) (see Threshold Analysis 2a in Table 8). As shown under T hreshold Analysis 1b, a charge size of 5,430 grams, or approximately forty times greater than the typic al charge size indicated by the submitter (i.e., 13 5 grams), should not be installed in a room smaller t han 244 m 3 . To avoid exposures that exceed the 30-min AEGL for propane from the release of a 135-gram uni t, the volume of the room should not be less than approximately 6 m 3 (200 ft 3 ), or approximately forty times smaller than the vo lume of the modeled restaurant kitchen (see Threshold Analysis 2b).March 28, 2016 – Final 14 To prevent exposure and potential serious side effe cts during larger releases, EPA recommends that the RCL for propane (i.e., 5,300 ppm or 9.5 g/m 3 ) is not exceeded in any location where a propane s ystem is installed, unless proper leak protection devices ar e in place in order to prevent exposures of propane beyond the recommended limits. Proper leak protecti on devices, engineering control requirements, and adherence to the SDS will further ensure that expos ure limits are maintained below those described in Table 8.



### 10. OCCUPATIONAL EXPOSURE ASSESSMENT
This section assesses potential exposures to worker s during manufacture of propane, installation, serv icing, and disposal of propane water coolers. To ensure th at use of the proposed substitute in water coolers does not pose an unacceptable toxicity risk to workers d uring servicing and disposal, occupational exposure modeling was performed using a box-model approach. For a detailed description of the methodology used for this screening assessment, the reader is referr ed to the occupational exposure and hazard analysis described in Chapter 5 of the Background Document. For charging, servicing, and disposal activities, t he release rate per event was multiplied by the num ber of events estimated to occur over a workday. During ch arging and servicing, the release per event was conservatively assumed be 0.4 percent of the equipm ent charge. For equipment charging and servicing, t he number of events per workday was conservatively ass umed that eight events of servicing a unit by one servicing technician occur in an 8-hour work day (s ee Section 10.2). For disposal, the release per event was conservativ ely assumed to be 100 percent of the equipment char ge (representing a catastrophic release). It was assum ed that 10 units are disposed of during an 8-hour w ork day; however, it was assumed that of the 10 units, only the last unit per workday would experience the catastrophic release (i.e., 100 percent). The remai ning 9 units were assumed to release an incidental amount of refrigerant (i.e., 1 percent per unit) fr om the connecting and disconnecting of lines, as it is likely that if a worker was exposed to the entire charge o f a system during disposal activities, they would immediately stop working, clear the area until all refrigerant has been removed from the space (e.g., through ventilation), and adhere to the exposure pr ocedures recommended in the SDS for the proposed substitute (see Section 10.3). The modeled exposure concentrations were compared t o short-term occupational exposure limits at charging and servicing and long-term exposure limit s at disposal. 10.1 Occupational Exposure at Manufacture of Substi tute Propane is produced around the world, including in the United States, and is used for a wide variety o f refrigerant and non-refrigerant uses. The submitter does not intend to manufacture propane in the Unit ed States. Nevertheless, during manufacture of propane , the SDS should be referenced and proper engineeri ng controls and PPE used. Propane is not expected to pose a risk to workers d uring manufacture or blending when the engineering controls and PPE recommendations referenced in the SDS propane are followed. Release points/exposure in chemical manufacturing would typically be where temporary lines are connected or disconnected (i.e.

, filling of portable cylinders and portable bulk con tainers). Refrigerant quality control testing may r esult in release of de minimus quantities of refrigerant, which would typically be to exhaust ducts or fume hoods. Engineering controls should include normal and loca l ventilation (e.g., chemical hoods) and vapor-in-a ir detection systems for standard manufacturing proced ures so workers can avoid physical contact with the refrigerant and to achieve emission control. In gen eral, use of PPE consistent with OSHA guidelines isMarch 28, 2016 – Final 15 recommended, such as respiratory protection (includ ing a self-contained breathing apparatus [SCBA] in case of insufficient ventilation), tightly sealed g oggles, and protective gloves (OSHA 1994). EPA beli eves that when proper handling and disposal guidelines a re followed in accordance with both good industrial hygiene and manufacturing practices and the SDS for propane, there is no significant risk to workers during the manufacture of propane. 10.2 Occupational Exposure at Charging and Servicin g Water coolers would typically be charged by the Ori ginal Equipment Manufacturer (OEM). During OEM system manufacture (i.e., charging at OEM location) , points of release for charging and servicing thes e leak-tight systems would be from connection/disconn ection of temporary lines for charging and recovery equipment. Charging occurs within an enclosed area equipped wi th automatic ventilation, refrigerant detectors, an d alarm systems. Release points during charging would be connection/disconnection of temporary lines fro m charging equipment prior to being hermetically seal ed. During servicing, used refrigerant from propane water coolers is pumped into a canister, where it i s stored until it is recycled (i.e., filtered and r eused). Isolation and evacuation of lines or equipment prio r to servicing or repair and the use of compatible seals, gaskets, O-rings, thread sealants, and minimization of threaded joints all contribute to limiting rele ases. Room ventilation, leak monitors, and alarms also mi nimize exposure. Installation and servicing activities for water coo lers are not expected to result in significant work er exposure when certified technicians follow the proc edures outlined in the propane SDS and maintenance manual, undergo proper training, and wear appropria te PPE (e.g., gloves and safety glasses). Neverthel ess, the potential occupational exposure during servicin g was analyzed. The maximum 30-minute TWA exposures for propane were estimated and compared t o the STEL (see Table 8). The modeling results indicate that the maximum anticipated occupational exposure concentrations at no point exceed the STEL for propane. Table 8. Occupational Risk Assessment at Servicing a

Component 30-minute TWA Occupational Exposure (ppm) Short Term Exposure Limit (ppm) Charge Size: 60 grams Charge Size: 135 grams Propane 0.48 1.1 6,900 b Bold font indicates modeling results.

a Cells highlighted in green are the scenarios that a re deemed to be acceptable given various modeling assumption options.

b 30-minute AEGL-1; see Table 4 for more information. The estimated exposures were derived using conserva tive assumptions, and represent a worst-case scenar io with a low probability of occurrence. These types o f systems are typically serviced by trained personn el using proper industrial hygiene techniques and usin g proper engineering controls (e.g., local ventilat ion, refrigerant detectors, and alarm systems). Thus, EP A does not believe that installation or servicing o f water coolers containing propane presents a significant c oncern to workers. 10.3 Occupational Exposure at Disposal Disposal of propane water coolers is expected to oc cur with limited frequency (up to approximately ten disposal events per day) at disposal facilities and with limited duration of exposure to the installed refrigerant. Typically, potential exposures to the refrigerant during recovery and disposal are expect ed to occur during activities related to decommissioning refrigeration systems (e.g., attaching of hoses associated with draining or otherwise discharging o f refrigerant from the refrigeration units into cyl inders) and would be similar to those during servicing, bec ause similar refrigerant charging and/or recoveryMarch 28, 2016 – Final 16 equipment would be used (see Section 10.2 and Table 8 for information and modeling results related to exposure during servicing activities). Table 9 displays the maximum estimated 8-hour TWA o ccupational exposure levels for propane and each of its potential impurities during disposal. To mod el a worst-case scenario, it was assumed that of th e 10 disposal events, 9 units are properly disposed of w ith only incidental releases of refrigerant (i.e., 1 percent per unit) followed by the disposal of one unit that results in a catastrophic release of refrigerant ( i.e., 100 percent of the equipment charge). Because modeled e xposure levels for both the 60-gram and 135-gram charge sizes are significantly lower than the 8-hou r exposure limits for propane and each of its poten tial impurities, occupational exposure to the proposed s ubstitute during disposal is not considered a toxic ity risk. Further, estimated exposures were derived usi ng conservative assumptions (e.g., no ventilation) and represent a worst-case scenario with a low probabil ity of occurrence. These types of systems are typic ally disposed of by trained personnel using proper indus trial hygiene techniques while wearing PPE. Table 9. Occupational Risk Assessment at Disposal a
Component 8

- hour TWA Occupational Exposure (ppm) 8-Hour Long Term Exposure Limits (ppm) Charge Size: 60 grams Charge Size: 1 35 grams Propane 2 3 52 1,000 b Bold font indicates modeling results.

a Cells highlighted in green are the scenarios with e xposure levels deemed to be acceptable given variou s modeling assumption options.

b OSHA PEL and NIOSH REL

c NIOSH REL

d ACGIH TLV Although anticipated occupational exposures are wel l below the exposure limit for propane for units wi th a charge of 60 grams and 135 grams, the recommendatio ns for proper engineering controls and PPE in the SDS for propane should be followed. Adequate ventil ation should always be established during any use, handling, or storage of propane. Engineering contro ls should include vapor-in air detection systems an d local exhaust ventilation during use of propane to prevent dispersion throughout the workplace. In addition, an eye wash and safety shower should be n ear locations where propane is stored and ready for use. In general, use of PPE is recommended, such as splash goggles, mechanically-resistance gloves whe n handling cylinders, and chemically-resistant gloves when handling the gas mixture (e.g., butyl rubber, chlorinated polyethylene, or neoprene). EPA believe s that if proper handling and disposal guidelines a re followed in accordance with good industrial hygiene and manufacturing practices and the SDS for propane, there is no significant risk to workers du ring the disposal of propane in water coolers.



### 11. GENERAL POPULATION EXPOSURE ASSESSMENT
This section presents an assessment of potential ri sks to the general population posed by the use of p ropane in water coolers. The general population is defined in this risk screen as non-personnel who are subje ct to exposure of the proposed substitute near industrial facilities, including manufacturing or equipment production factories, equipment operating sites (fo r on-site installation or disposal activities only) , or recycling centers, rather than consumers at end-use

. Propane is not expected to cause a significant risk to human health in the general population when manufactured for use and used as a refrigerant in w ater coolers. The proposed substitute will be manufactured in a closed process and is proposed fo r use in closed systems; thus, significant releases are not anticipated. At room temperature, propane is a gas; therefore, releases to ground or surface water are not anticipated, as propane is anticipated to dissi pate into the atmosphere upon release to outside ai r (i.e.,March 28, 2016 – Final 17 because natural ventilation rates would be higher a nd there is no enclosed space to maintain a high concentration of propane). Should air releases duri ng manufacturing operations occur, engineering cont rols should be used (e.g., carbon absorption scrubbers) to collect propane and prevent the release of the chemical to the atmosphere. EPA believes that by us ing proper engineering controls and by following disposal and containment recommendations outlined i n the proposed substitute’s SDS and this risk scree n, exposure to propane is not expected to pose a signi ficant toxicity risk to the general population.March 28, 2016 – Final 18 

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