On December 27, 2020, the American Innovation and Manufacturing (AIM) Act of 2020 was enacted in the 2021 Consolidated Appropriations Act. The AIM Act directs the Environmental Protection Agency (EPA) to address hydrofluorocarbons (HFCs) by phasing down the production and import of listed HFCs, managing these HFCs and their substitutes, and facilitating the transition to next-generation technologies. HFC production will be phased down to 15% of current levels by 2036. This follows the same phase down schedule being implemented globally under the Montreal Protocol’s Kigali Amendment, which was ratified in the U.S. Senate in September 2022. Per the AIM Act and EPA regulation, DoD receives HFC allowances to meet mission-critical military end uses (MCMEU). DoD, through inter-Service coordination, is working with the EPA to secure and report the DoD MCMEU allowances. However, there is no guarantee that domestic chemical companies will continue to produce HFCs as overall HFC production limits are phased in.
The AIM Act lists specific HFCs that are commonly used in fire suppression for phase-down, including HFC-227ea, HFC-125, HFC-236fa and HFC-23. HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) is a widely used fire suppressant in military fire suppression systems on ships and expeditionary/amphibious/combat vehicles. There is a single U.S. domestic production facility for HFC-227ea, with additional suppliers in non-allied countries. HFC-227ea has uses in the medical industry that are allowed under the current structure of the AIM Act; however, industry is actively seeking lower GWP alternatives and anticipates phase down of production and import as soon as alternatives are identified. DoD has evaluated multiple alternative agents in fuel-spray live-fire tests designed to simulate fireball development and blast overpressure that follows a ballistic penetration of the vehicle armor and fuel tank. Test criteria were derived to allow vehicle occupants to remain in the compartment for at least five minutes during and following a fire suppression event without being subjected to immediate or delayed incapacitation. There is no approved alternative for the HFC-227ea used in fire suppression for military uses Overall, it has been found that gaseous low GWP alternatives are more reactive, resulting in shorter atmospheric lifetimes and therefore lower GWPs, also generate much higher levels of toxic gases compared to the more stable, higher GWP chemicals.