CHEMICAL UPDATE WORKSHEET Chemical Name: Dichlorodifluoromethane CAS #: 75-71-8 Revised By: RRD Toxicology Unit Revision Date: August 17, 201 (A) Chemical-Physical Properties Part 201 Value Updated Value Reference Source Comments Molecular Weight (g/mol) 120.91 120.91 EPI EXP Physical State at ambient temp Liquid Gas MDEQ Melting Point (˚C) 138 -158.00 EPI EXP Boiling Point (˚C) -29.8 -29.80 EPI EXP Solubility (ug/L) 3.00E+5 2.80E+05 EPI EXP Vapor Pressure (mmHg at 25˚C) 4864 4.85E+03 EPI EXP HLC (atm-m³/mol at 25˚C) 2.60 3.43E-01 EPI EXP Log Kow (log P; octanol-water) 2.15 2.16 EPI EXP Koc (organic carbon; L/Kg) 60.4 43.89 EPI EST Ionizing Koc (L/kg) NR NA NA Diffusivity in Air (Di; cm2/s) 0.08 7.30E-02 W9 EST Diffusivity in Water (Dw; cm2/s) 8.0E-6 1.0233E-05 W9 EST Soil Water Partition Coefficient NR NR NA NA (Kd; inorganics) CHEMICAL UPDATE WORKSHEET Dichlorodifluoromethane (75-71-8) Part 201 Value Updated Value Reference Source Comments Flash Point (˚C) NA NA NA NA Lower Explosivity Level (LEL; NA NA NA NA unit less) Critical Temperature (K) 384.95 EPA2004 EXP Enthalpy of Vaporization 9.42E+03 EPA2004 EXP (cal/mol) 3 Density (g/mL, g/cm ) 1.35 PC EXP EMSOFT Flux Residential 2 m 2.71E-05 2.81E-05 EMSOFT EST (mg/day/cm2) EMSOFT Flux Residential 5 m 6.67E-05 6.93E-05 EMSOFT EST (mg/day/cm2) EMSOFT Flux Nonresidential 2 m 3.87E-05 4.49E-05 EMSOFT EST (mg/day/cm2) EMSOFT Flux Nonresidential 5 m 9.48E-05 1.10E-04 EMSOFT EST (mg/day/cm2) 2 CHEMICAL UPDATE WORKSHEET Dichlorodifluoromethane (75-71-8) (B) Toxicity Values/Benchmarks Source/Reference/ Comments/Notes Part 201 Value Updated Value Date /Issues PPRTV, Reference Dose 2.3E-1 5.0E-3 (RfD) (mg/kg/day) 2010/MDEQ 2015 Tier 2 Source: Complete PPRTV: Basis: PPRTV is a more current evaluation than IRIS. PPRTV (9/29/2010) subchronic p-RfD = 5.0E-2. MDEQ applied an additional UF = 10 for use of a Rat chronic subchronic exposure study. PPRTV notes that the subchronic p-RfD is lower than dietary study the IRIS RfD as a database uncertainty factor was not considered at the time that (Sherman 1974). the IRIS chronic RfD was derived. NOAEL = 300; UF Critical Study (ies): Sherman, H. (1974) Long-term feeding studies in rats and dogs = 100. (300mg/kg with dichlorodifluoromethane (FREON 12 food freezant). Haskell Laboratory for x 0.076kg/kg bw = Toxicology and Industrial Medicine. Medical Research Project No. 1388. Haskell 22.8/100 = Laboratory Report No. 24–74. Unpublished study conducted for DuPont de 0.23mg/kg/day). Nemours Co. Critical effect = Method(s): Long-term oral toxicity studies in two species (rats and dogs) and a reduced body multi-generation reproductive toxicity study in rats. Weanling Charles River CD RfD details weight. *IRIS oral rats (50/sex/dose) from dams exposed during gestation were administered RfD (2E-1) dichlorodifluoromethane (purity not reported) via gavage at 0, 0.2, or 2% in corn changed. oil 7 days/week for 6 weeks and 5 days/week thereafter for 2 years The chronic Replaced IRIS rat study includes quarterly tabulation (i.e., every 3 months) of average body- assumed rat food weight gains. In female rats, compared to controls, exposure was associated with consumption a significant (i.e., >10%) reduced body-weight gain in every quarter from initiation value with MDNR to terminus of study. For the first quarter, Days 0–91 of the study, a sub chronic default value. LOAEL of 150 mg/kg-day and NOAEL of 15 mg/kg-day are identified based on a Source: IRIS reduction in body-weight gain in females. Sherman (1974) also administered CCD/RRD date: dichlorodifluoromethane (purity not specified) to Beagle dogs (4/sex/dose) at 0, 7/22/1985 300, or 3,000 ppm in the diet for 2 years. Critical effect: decreased body-weight gain End point or Point of Departure (POD): NOAEL = 15 mg/kg-day (Although NOAELs are also available from the studies for systemic toxicity in dogs (Sherman, 1974), reproductive toxicity in rats (Sherman, 1974), and developmental toxicity in rats 3 CHEMICAL UPDATE WORKSHEET Dichlorodifluoromethane (75-71-8) Source/Reference/ Comments/Notes Part 201 Value Updated Value Date /Issues (Culik and Sherman, 1973) these occurred at higher dichlorodifluoromethane doses) Uncertainty Factors: UF = 300 (10 each for interspecies variability and interspecies extrapolation, and 3 for database inadequacies) Source and date: PPRTV, 9/29/2010 Tier 1 and 2 Sources: IRIS: Per IRIS (11/01/1995), RfD = 2.0E-1 mg/kg-day. The RfD was derived as follows: Critical Study: Sherman, H. 1974. Long-term feeding studies in rats and dogs with dichlorodifluoromethane (Freon 12 Food Freezant). Haskell Laboratory for Toxicology and Industrial Medicine Report No. 24-74.) Method(s): Dogs and rats were exposed to 300 ppm or 3,000 ppm of dichlorodifluoromethane in the diet for 2 years Critical effect: reduced body weight End point or Point of Departure (POD): NOAEL = 300 ppm (converted to 15 mg/kg/day assuming 1 ppm = 0.05 mg/kg-day rat consumption) Uncertainty Factors: UF = 100 (10 each for interspecies variability and interspecies extrapolation) Source and date: IRIS, Last revision date - 11/01/1995. An IRIS comprehensive review of toxicological studies in 2005 did not identify significant new data. MRL: No MRL record available at this time. Tier 3 Source: MDEQ: Per DEQ-CCD/RRD (7/22/1985), RfD = 2.3E-1 mg/kg-day. See Part 201 Value RfD details. Oral Cancer Slope Factor (CSF) -- NA MDEQ, 2015 (mg/kg-day)-1) Carcinogen Weight-of-Evidence (WOE) Class: “Inadequate Information to Assess Complete [the] Carcinogenic Potential” NA CSF details IRIS WOE Basis: human cancer data are lacking, and the available animal data are inadequate to assess potential carcinogenicity. Genotoxicity data are primarily 4 CHEMICAL UPDATE WORKSHEET Dichlorodifluoromethane (75-71-8) Source/Reference/ Comments/Notes Part 201 Value Updated Value Date /Issues negative. Source and Date: PPRTV, 9/29/2010 Tier 1 and 2 Sources: IRIS: Per IRIS (11/01/1995), no value at this time. IRIS has not evaluated dichlorodifluoromethane for evidence of carcinogenic potential. PPRTV: Per PPRTV (9/29/2010), no value at this time. MRL: NA; MRLs are for non-cancer effects only. Tier 3 Source: MDEQ: Per DEQ-CCD, no value at this time. Reference Concentration PPRTV, (RfC) or Initial 4.95E+4 3.3 E+2 Threshold 2010/MDEQ, 2015 Screening Level (ITSL) (µg/m³) ACGIH TLV key Tier 3 Source: Complete study based on PPRTV: Prendergast et al. Basis: PPRTV evaluation is more current than IRIS. PPRTV (9/29/2010) subchronic (1967). p-RfD = 1.0E+0 mg/m3 . MDEQ applied an additional UF of 3 to account for Hepatonecrosis subchronic to chronic exposure extrapolation to derive a chronic RfC = 3.3E-1 and potential mg/m3 (3.3E+2 µg/m3). The composite UF is 3,000. This value has lower pulmonary uncertainty than the PPRTV Screening Value that EPA considers a Tier 3 source. impacts were PPRTV sub chronic p-RfD derivation: RfC/ITSL details seen in guinea Critical Study: Prendergast, JA; Jones, RA; Jenkins, LJ; et al. (1967) Effects on pigs following 90 experimental animals of long term inhalation of trichloroethylene, carbon days continuous tetrachloride, 1,1,1-trichloroethane, dichlorodifluoromethane and 1,1- inhalation dichloroethylene. Toxicol Appl Pharmacol 10(2):270–289. exposure. Method(s): 6-week intermittent inhalation study in guinea pigs, rabbits, dogs, and TLV/100 X 1000 = monkeys ITSL. Critical effect: reduced body weight gain 3 CCD/AQD date: End point or Point of Departure (POD): LOAELHEC = 985 mg/m 7/05/2001. Uncertainty Factors: UF = 1,000 (10 each for interspecies variability and use of a 5 CHEMICAL UPDATE WORKSHEET Dichlorodifluoromethane (75-71-8) Source/Reference/ Comments/Notes Part 201 Value Updated Value Date /Issues LOAEL and 3 (100.5) each for interspecies extrapolation and database inadequacies). Source and date: PPRTV, 9/29/2010. Tier 1 and 2 Sources: IRIS: Per IRIS (1/31/1987), no value at this time. PPRTV: PPRTV (9/29/2010) chronic inhalation screening level p-RfC = 1.0E-1 mg/m3. Per PPRTV, a provisional chronic RfC cannot be confidently derived from the Prendergast study die to the high level of overall uncertainty associated with using a 6-week data. EPA considers Screening Value a Tier 3 source. Critical Study: Prendergast, JA; Jones, RA; Jenkins, LJ; et al. (1967) Effects on experimental animals of long term inhalation of trichloroethylene, carbon tetrachloride, 1,1,1-trichloroethane, dichlorodifluoromethane and 1,1- dichloroethylene. Toxicol Appl Pharmacol 10(2):270–289. Method(s): 6-week intermittent inhalation study in guinea pigs, rabbits, dogs, and monkeys Critical effect: reduced body weight gain 3 End point or Point of Departure (POD): LOAELHEC = 985 mg/m Uncertainty Factors: UF = 10,000 (10 each for interspecies variability, use of a LOAEL and use of a sub chronic study, and 3 each for interspecies extrapolation and database inadequacies) Source and date: PPRTV, 9/29/2010. MRL: No MRL record available at this time. Tier 3 Source: MDEQ: Per DEQ-CCD/AQD (7/05/2001), RfC = 4.95E+4 µg/m3. See Part 201 Value RfC/ITSL details. Inhalation Unit Risk Factor -- NA MDEQ, 2015 (IURF) ((µg/m3)-1) Carcinogen Weight-of-Evidence (WOE) Class: “Inadequate Information to Assess Complete IURF details NA [the] Carcinogenic Potential” IRIS WOE Basis: human cancer data are lacking, and the available animal data are 6 CHEMICAL UPDATE WORKSHEET Dichlorodifluoromethane (75-71-8) Source/Reference/ Comments/Notes Part 201 Value Updated Value Date /Issues inadequate to assess potential carcinogenicity.