A House subcommittee chairman charged that private companies hired by the Defense Department have improperly dumped thousands of gallons of highly toxic wastes generated at military installations.
Rep. Michael Synar (D) of Oklahoma said tens of thousands of gallons of PCBs handled by the private companies remain ''unaccounted for,'' according to records. Production of PCBs, or polychlorinated biphenyls, was banned in 1976.
Mr. Synar said one contractor, American Electric Corporation, tried to ship thousands of gallons of PCBs to Honduras, using falsified papers. Synar also said water supplies for Tucson, Ariz., Jacksonville, Fla., and Phoenix, Md., have been contaminated by Defense Department wastes.