The FAA is issuing an update of advisory circular AC 20-42D: Hand Fire Extinguishers for Use in Aircraft. It provides guidance for firefighting effectiveness, selection, location and mounting of hand fire extinguishers. The circular establishes halocarbons hydrochlorofluorocarbon (HCFC) Blend B, hydrofluorocarbon (HFC)-227ea and HFC-236fa as FAA-approved replacement agents to Halon 1211. According to the AC, replacement halocarbon clean agents were developed in response to restrictions on the production of ozone-depleting halon fire-extinguishing agents. Halon 1211 has not been produced in the U.S. since 1994, and by next year it will not be produced anywhere in the world. Halocarbon clean agent extinguishers are now commercially available and after evaluation have been found to be effective firefighting agents. According to the FAA, if used properly, they are safe to human health and the environment. In addition, the safe-use guidance in the AC for Halon 1211 is more conservative, the standard for safety is higher than the previous AC, and is based on a better understanding of the toxicology of halocarbons.