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SESK: Stuff Everyone Should Know · sesk.info/epa-a2l-meaning

R-32 and R-454B are classed A2L. In plain words, what kind of refrigerants are they?

Mildly flammable.

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  1. Mildly flammable ✔
  2. Nonflammable
  3. Highly toxic

Why: EPA describes refrigerants such as HFC-32 and R-454B as mildly flammable, and its SNAP list shows them as class A2L. They need extra care around ignition sources.

Huh, didn't know that: EPA lists HFC-32 with a GWP of 675 and class A2L, acceptable with use conditions.

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References

Answer: Mildly flammable. EPA describes refrigerants such as HFC-32 and R-454B as mildly flammable, and its SNAP list shows them as class A2L. They need extra care around ignition sources.

  1. Frequent Questions on the Phasedown of HFCs, US EPA www.epa.gov/hfcs/frequent-questions-phasedown-hydrofluorocarbons
    flammable or mildly flammable refrigerants such as HFC-32 or R-454B
    Checked 2026-10-10.
  2. SNAP substitutes in residential and light commercial AC and heat pumps, US EPA www.epa.gov/snap/substitutes-residential-and-light-commercial-air-conditioning-and-heat-pumps
    Acceptable with Use Conditions
    Checked 2026-10-10.

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