What is the ozone depletion potential of common fire suppression agents?

ExxFire · 28 Jun 2026

The ozone depletion potential of common fire suppression agents varies widely. Halon-based agents, once the industry standard, carry the highest ODP values, with Halon 1301 rated at 10 and Halon 1211 at 3 on the ODP scale. Modern replacements have largely eliminated measurable ozone depletion, though environmental concerns have shifted toward other hazards, including PFAS contamination and global warming potential.

Which fire suppression agents have the highest ozone depletion potential?

Halon-based fire suppression agents have the highest ozone depletion potential of any suppression chemicals. Halon 1301 (bromotrifluoromethane) carries an ODP of 10, meaning it is ten times more destructive to the ozone layer than the CFC-11 reference compound. Halon 1211 (bromochlorodifluoromethane), commonly used in portable extinguishers, carries an ODP of 3.

These figures explain why halons were among the first substances targeted under the Montreal Protocol in 1987. Bromine atoms, which halons release when exposed to ultraviolet radiation in the stratosphere, are far more reactive with ozone molecules than chlorine atoms are. A single bromine atom can destroy tens of thousands of ozone molecules before it is deactivated, making halons disproportionately harmful relative to the quantities used.

Other older agents, including carbon tetrachloride and certain chlorofluorocarbon-based suppressants, also carry significant ODP values. By contrast, dry chemical agents such as monoammonium phosphate and carbon dioxide carry an ODP of zero, though they introduce their own environmental and operational drawbacks.

What does ozone depletion potential actually measure?

Ozone depletion potential is a relative index that measures how much a given substance can damage the stratospheric ozone layer compared to a reference compound, CFC-11 (trichlorofluoromethane), which is assigned an ODP of 1.0. A substance with an ODP of 5 causes five times the ozone damage per kilogram released as CFC-11 does.

The calculation accounts for several factors: how long the substance persists in the atmosphere, how efficiently it releases ozone-reactive atoms, and how readily those atoms reach the stratosphere. This is why not all halogenated compounds are equally damaging. Fluorine-based compounds, for instance, tend to break down in the lower atmosphere before reaching the ozone layer, which is why many hydrofluorocarbon alternatives carry an ODP of zero even though they contain halogen atoms.

ODP is distinct from global warming potential (GWP), which measures a substance’s heat-trapping capacity. A suppression agent can have zero ODP but a very high GWP, which is why environmental assessments of fire suppression agents now evaluate both metrics together rather than treating ozone depletion as the sole concern.

Do modern clean agent alternatives still carry an ODP?

Most modern clean agent fire suppression alternatives have an ODP of zero. Hydrofluorocarbons (HFCs) such as HFC-227ea (FM-200) and HFC-125 were developed specifically to replace halons while eliminating ozone depletion potential, and they achieve that goal. Inert gas agents, including nitrogen, argon, and blends such as Inergen, also carry zero ODP because they contain no halogen atoms whatsoever.

However, eliminating ODP did not make all clean agents environmentally neutral. Many HFC-based suppressants carry very high global warming potentials. HFC-227ea, for example, has a GWP several thousand times that of carbon dioxide. This has prompted regulators in Europe and elsewhere to restrict or phase out high-GWP agents even where ODP is not a concern.

Perfluorocarbon-based agents (PFCs) present a different profile: zero ODP, zero acute toxicity, but extremely high atmospheric persistence and GWP. The environmental trade-off made in eliminating ozone-depleting substances was, in some cases, the introduction of persistent greenhouse gases, a problem the industry continues to address through further transitions toward inert gas and other low-impact alternatives.

Why is PFAS contamination now as concerning as ozone depletion?

PFAS contamination has become a central environmental concern in fire suppression because per- and polyfluoroalkyl substances persist indefinitely in the environment and accumulate in living organisms. Unlike ozone-depleting substances, which break down over decades, PFAS compounds do not degrade under natural conditions, earning the label “forever chemicals.” Their presence has been linked to soil and groundwater contamination, particularly around sites where aqueous film-forming foam (AFFF) has been used.

The regulatory response to PFAS in fire suppression has accelerated significantly. The European Union’s PFAS restriction proposal under REACH covers a broad range of fluorinated compounds, and many jurisdictions are moving to ban or severely restrict PFAS-containing suppression agents regardless of their ODP value. This means a suppression agent can have zero ozone depletion potential and still be subject to phase-out if it contains fluorinated chemistry.

For operators protecting sensitive electronics, PFAS contamination creates an additional operational risk. Residue from fluorinated agents can damage circuit boards and components, and cleanup after a suppression event involving PFAS-containing agents is costly and complex. The combination of regulatory pressure, environmental persistence, and hardware damage risk has made PFAS-free suppression a priority for facility managers and procurement teams across industries.

What fire suppression agents have both zero ODP and zero PFAS?

Inert gas agents, including pure nitrogen, argon, and approved inert gas blends, are the most complete answer to the dual requirement of zero ozone depletion potential and zero PFAS content. These agents contain no halogen atoms and no fluorinated chemistry, which means they carry no ODP, no GWP contribution from the agent itself, and no PFAS risk. Carbon dioxide also meets both criteria, though its use in occupied spaces carries life-safety constraints.

Water mist systems similarly carry zero ODP and zero PFAS, making them suitable for certain applications, though their use is limited in environments where water contact would damage sensitive electronics or electrical equipment.

The key distinction for mission-critical environments is that inert gas suppression, and nitrogen in particular, extinguishes fire by reducing oxygen concentration rather than introducing reactive chemistry. This mechanism leaves no residue, causes no secondary damage to electronics, and introduces no substances that require environmental remediation after deployment. For operators seeking to meet both current and anticipated future regulations, inert gas suppression represents the most future-proof option available.

How do international regulations control ODP in fire suppression?

The Montreal Protocol, adopted in 1987 and ratified by every member state of the United Nations, is the primary international instrument controlling ozone-depleting substances in fire suppression. It mandated the phase-out of halon production and consumption in developed nations by 1994, with developing nations following on a delayed schedule. As a result, new halon-based systems are no longer legally installed in most of the world, though existing “halon banks” are still maintained for critical aviation and military applications where no adequate alternative has been certified.

At the regional level, the European Union’s F-Gas Regulation extends control beyond ODP to include high-GWP fluorinated gases, effectively restricting many HFC-based suppression agents that replaced halons. This layered regulatory environment means that compliance now requires evaluating suppression agents against multiple environmental metrics simultaneously, not just ozone depletion potential.

National fire safety standards, including those set by NFPA in the United States and EN standards in Europe, incorporate these environmental restrictions into product certification requirements. Systems must be tested and certified to demonstrate both performance and environmental compliance, which is why independent third-party certification has become a standard procurement requirement for operators in regulated industries.

How ExxFire addresses the environmental impact of fire suppression

ExxFire’s integrated fire detection and suppression systems are built around pure nitrogen gas, the only suppression agent that simultaneously achieves zero ODP, zero PFAS content, zero GWP contribution, and zero chemical residue. For organizations managing switchgear cabinets, ICT enclosures, battery energy storage systems, or high-voltage equipment, this means complete protection without any of the environmental or operational liabilities associated with halon, HFC, or fluorinated alternatives.

Zero ODP and zero PFAS: Nitrogen is an inert gas with no halogen chemistry, making it fully compliant with current and anticipated future regulations under the Montreal Protocol, the EU F-Gas Regulation, and REACH PFAS restrictions.
No secondary damage: Nitrogen leaves no chemical residue, protecting sensitive electronics and eliminating costly post-suppression cleanup.
Non-pressurized storage: ExxFire’s patented Cool Gas Generator technology stores nitrogen in a solid, non-pressurized state, removing the safety and maintenance burden of high-pressure cylinders.
Early detection integrated: Aspirating smoke detection is built into the same unit, enabling suppression before a fire develops rather than after damage has already occurred.
Certified performance: Systems are independently tested and certified by CNPP in France and DMT, part of TÜV Nord in Germany, meeting the third-party verification requirements of regulated industries worldwide.

If your organization is evaluating a transition away from PFAS-containing or ozone-depleting suppression agents, contact ExxFire to discuss a solution built around the cleanest suppression chemistry available.