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Class II Ozone-Depleting Substances

Class II substances are listed in section 602 of the Clean Air Act, and comprise all HCFCs. All the 

class II substances and their isomers are regulated under the accelerated phaseout. These

compounds are numbered according to the ASHRAE Standard 34 scheme. 

The list of Class I substances (the CFCs) is here. 

GWPs for selected non-ozone-depleting substances are provided in another table. 

Why are there three values given for the ODPs and four values given for the GWPs?

The numbers in the “ODP-1” column are from Table 1-5 of The Scientific Assessment of 

Ozone Depletion, 2002, a report of the World Meteorological Association’s Global Ozone 

Research and Monitoring Project. The ODPs in the “ODP-1” column that were not in Table 1-

5 of the 2002 report have not been updated since 1998 and are from The Scientific 

Assessment of Ozone Depletion, 1998. The “ODP-2” column numbers are from the Montreal 

Protocol, and the “ODP-3” column numbers are from 40 CFR Part 82, stratospheric ozone 

protection regulations required by title VI of the Clean Air Act amendments. 

All GWP values represent global warming potential over a 100-year time horizon. The 

numbers in the “GWP-1” column are from Table 1-6 of The Scientific Assessment of Ozone 

Depletion, 2002, a report of the World Meteorological Association’s Global Ozone Research 

and Monitoring Project. The GWPs in the “GWP-1” column that were not provided in Table 1-

6 of the 2002 report have not been updated since 1998 and are from The Scientific 

Assessment of Ozone Depletion, 1998. “GWP-2” column numbers are from the 

Intergovernmental Panel on Climate Change (IPCC ) Second Assessment 

Report: Climate Change 1995, “GWP-3” column numbers are from the IPCC Third

Assessment Report: Climate Change 2001, and “GWP-4” column numbers are from 40 CFR 

Part 82, stratospheric ozone protection regulations required by title VI of the Clean Air Act

amendments.

Under section 602, EPA was required to list in the Federal Register the GWPs for ozone-depleting

substances. That list was published on January 19, 1996.

 Blanks in the data indicate that the information was not shown in the original source. 

Chemical Name Lifetime,

in years

ODP1 

(WMO 

20021)

ODP2 

(Montreal 

Protocol)

ODP3 

(40 

CFR)

GWP1 

(WMO 

2002)

GWP2 

(SAR)

GWP3 

(TAR)

GWP4 

(40 

CFR)

CAS 

Number

HCFC-21 (CHFCl2)

Dichlorofluoromethane 1.7 0.04 0.04 148 210 75-43-

4

HCFC-22 (CHF2Cl)

Monochlorodifluoromethane 12.0 0.05 0.055 0.05 1780 1500 1700 1700 75-45-

6

HCFC-31 (CH2FCl)

Monochlorofluoromethane 0.02 0.02 593-

70-4

HCFC-121 (C2HFCl4)

Tetrachlorofluoroethane

0.0 1

- 0.04

0.01-

0.04

354-

14-3

HCFC-122 (C2HF2Cl3)

Trichlorodifluoroethane

0.02 -

0.08

0.02 -

0.08

354-

21-2

HCFC-123 (C2HF3Cl2)

Dichlorotrifluoroethane 1.3 0.02 0.02 -

0.06 0.02 76 90 120 93 306-83-2

HCFC-124 (C2HF4Cl) 0.02 - 2837-

U.S. EPA: Class II Ozone-Depleting Substances Page 1 of 3

http://www.epa.gov/ozone/ods2.html 2/15/2007
Monochlorotetrafluoroethane 5.8 0.02 0.04 0.02 599 470 620 480 89-0

HCFC-131 (C2H2FCl3)

Trichlorofluoroethane

0.007

- 0.05

0.007 -

0.05

359-

28-4

HCFC-132b (C2H2F2Cl2)

Dichlorodifluoroethane

0.008

- 0.05

0.008 -

0.05

1649-

08-7

HCFC-133a (C2H2F3Cl)

Monochlorotrifluoroethane

0.02 -

0.06

0.02 -

0.06

75-88-

7

HCFC-141b (C2H3FCl2)

Dichlorofluoroethane 9.3 0.12 0.11 0.1 713 700 630 1717-

00-6

HCFC-142b (C2H3F2Cl)

Monochlorodifluoroethane 17.9 0.07 0.065 0.06 2270 1800 2400 2000 75-68-

3

HCFC-221 (C3HFCl6)

Hexachlorofluoropropane

0.015 

- 0.07

0.015 -

0.07

422-

26-4

HCFC-222 (C3HF2Cl5)

Pentachlorodifluoropropane

0.01 -

0.09

0.01 -

0.09

422-

49-1

HCFC-223 (C3HF3Cl4)

Tetrachlorotrifluoropropane

0.01 -

0.08

0.01 -

0.08

422-

52-6

HCFC-224 (C3HF4Cl3)

Trichlorotetrafluoropropane

0.01 -

0.09

0.01 -

0.09

422-

54-8

HCFC-225ca (C3HF5Cl2)

Dichloropentafluoropropane 1.9 0.02 0.025 120 180 170 422-

56-0

HCFC-225cb (C3HF5Cl2)

Dichloropentafluoropropane 5.8 0.03 0.033 586 620 530 507-

55-1

HCFC-226 (C3HF6Cl)

Monochlorohexafluoropropane

0.02 -

0.1

0.02 -

0.1

431-

87-8

HCFC-231 (C3H2FCl5)

Pentachlorofluoropropane

0.05 -

0.09

0.05 -

0.09

421-

94-3

HCFC-232 (C3H2F2Cl4)

Tetrachlorodifluoropropane

0.008 

- 0.1

0.008 -

0.1

460-

89-9

HCFC-233 (C3H2F3Cl3)

Trichlorotrifluoropropane

0.007 

- 0.23

0.007 -

0.23

7125-

84-0

HCFC-234 (C3H2F4Cl2)

Dichlorotetrafluoropropane

0.01 -

0.28

0.01 -

0.28

425-

94-5

HCFC-235 (C3H2F5Cl)

Monochloropentafluoropropane

0.03 -

0.52

0.03 -

0.52

460-

92-4

HCFC-241 (C3H3FCl4)

Tetrachlorofluoropropane

0.004 

- 0.09

0.004 -

0.09

666-

27-3

HCFC-242 (C3H3F2Cl3)

Trichlorodifluoropropane

0.005 

- 0.13

0.005 -

0.13

460-

63-9

HCFC-243 (C3H3F3Cl2)

Dichlorotrifluoropropane

0.007 

- 0.12

0.007 -

0.12

460-

69-5

HCFC-244 (C3H3F4Cl)

Monochlorotetrafluoropropane

0.009 

- 0.14

0.009 -

0.14

HCFC-251 (C3H4FCl3)

Trichlorofluoropropane

0.001 

- 0.01

0.001 -

0.01

421-

41-0

HCFC-252 (C3H4F2Cl2)

Dichlorodifluoropropane

0.005 

- 0.04

0.005 -

0.04

819-

00-1

HCFC-253 (C3H4F3Cl)

Monochlorotrifluoropropane

0.003 

- 0.03

0.003 -

0.03

460-

35-5

HCFC-261 (C3H5FCl2)

Dichlorofluoropropane

0.002 

- 0.02

0.002 -

0.02

420-

97-3

HCFC-262 (C3H5F2Cl)

Monochlorodifluoropropane

0.002 

- 0.02

0.002 -

0.02

421-

02-03

HCFC-271 (C3H6FCl)

Monochlorofluoropropane

0.001 

- 0.03

0.001 -

0.03

430-

55-7

U.S. EPA: Class II Ozone-Depleting Substances Page 2 of 3

http://www.epa.gov/ozone/ods2.html 2/15/2007
1 The Scientific Assessment of Ozone Depletion, 2002 updated a limited number of GWPs and 

ODPs (semiempirical values for all updated ODPs except CFC-114 and CFC-115, which are modelderived). All GWPs and ODPs that were not updated in 2002 are 1998 values that have not

changed.

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Last updated on Wednesday, March 8th, 2006

URL: http://www.epa.gov/ozone/ods2.html 

U.S. EPA: Class II Ozone-Depleting Substances Page 3 of 3

http://www.epa.gov/ozone/ods2.html 2/15/2007