- Ozone Depleting Potential
Ozone Depletion Potential (ODP) is a relative measure used to indicate the amount of degradation a chemical compound causes to the ozone layer as an Ozone Depleting Substance compared to a reference substance.
The standard reference gas used for this scale is CFC-11 (trichlorofluoromethane), which is assigned an ODP value of 1.0.
The Ozone Depletion Potential of a substance is determined by several chemical factors:
- Chlorine or Bromine Content: The number of ozone-destroying atoms the molecule carries.
- Atmospheric Lifetime: How long the chemical stays intact. If a chemical breaks down before reaching the stratosphere, its ODP is low.
- Photochemical Stability: How easily the molecule is broken apart by UV radiation to release its reactive atoms.
Substance Class Common Name ODP11 Lifetime (Years) GWP1P2 (100-Year) Status CFCs CFC-11 (Reference) 1 45 4660 Phased Out Halons Halon 1211
Halon 1301
Halon 24023
10
616
65
201750
6290
1470Extremely high; production banned HCFCs HCFC-123 (Halotron I) 0.02 77 Transitional; being phased out HFCs HFC-227ea (FM-200) 0.0 3500 Zero ODP, but high Global Warming Potential Fluoroketones Novec 1230 0.0 <1 Modern sustainable alternative Inert Gas Blend Inergen (IG-541) 0.0 0 No known impact on ozone or climate. Inert Gasses Nitrogen / Argon 0.0 0 Naturally occurring; no atmospheric impact. Halons have a very high ODP (up to 10.0) because they contain bromine, which is roughly 60 times more efficient at destroying ozone than the chlorine found in CFCs. This high ODP is the primary reason the Montreal Protocol forced the aviation industry to find alternative "Clean Agents" despite halon's superior fire-extinguishing performance.
- 1
Ozone Depletion Potential (ODP) values for regulated substances are determined relative to CFC-11 (ODP = 1.0) as codified by the U.S. Environmental Protection Agency (EPA) under the framework of the Montreal Protocol. See: https://www.epa.gov/ozone-layer-protection/ozone-depleting-substances. [May 1, 2026]
- 2
Global Warming Potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere over a specific period of time, compared to Carbon Dioxide CO2.