Air Force Plant 42 is a superfund site located at 20th St E & Aves O & M, Palmdale, CA 93550. The Environmental Protection Agency (EPA) identifies sites such as Air Force Plant 42 because they pose or had once posed a potential risk to human health and/or the environment due to contamination by one or more hazardous wastes. Air Force Plant 42 is currently registered as an Active superfund site by the EPA. However, it is not on the NPL (National Priorities List), which means the EPA does not consider it one of the nation's most hazardous waste sites.