The Environmental Protection Agency yesterday proposed allowing firms that produce polychlorinated biphenyls, or PCBs, in their manufacturing process to regulate themselves for the most part, with only sporadic checks by the agency.

EPA said that requiring firms to submit data for the agency to review and approve would be "very costly and burdensome to industry and EPA."

But Jackie Warren, an attorney with the Natural Resources Defense Council, said, "It the proposal leans heavily on voluntary compliance, which hasn't seemed to work that well."

Jeff Van, a spokesman for the Chemical Manufacturers Association, said CMA is waiting for more details on the plan "before making any judgments."

PCBs are thought by some scientists to be carcinogenic in humans, although the chemical and electrical industries have recently argued that PCBs do not pose a health hazard. In 1976, Congress directed EPA to ban the use or manufacture of PCBs in any form that might significantly expose humans or the environment.

PCBs have not been produced for sale for three years, but they are still produced inadvertently as a byproduct in some industries, including those making organic chemicals and pigments and dyes. PCBs can also still be found in most major electrical equipment.

Two years ago, a court threw out some of EPA's rules on PCBs, saying that the agency had failed to deal adequately with the PCBs from electrical equipment and from those produced inadvertently. EPA is under court order to complete its regulations for restricting PCBs in electrical equipment by August, and is now holding four days of hearings on that issue.

The final rule on PCBs produced in manufacturing is due in October. Under the rule proposed yesterday, if PCBs are produced and destroyed in a totally enclosed atmosphere, or if PCBs are totally disposed of by incineration or in an EPA-approved landfill, the firm doesn't have to comply with the ban.

It would be up to firms to decide if they qualify for either category and to keep records that EPA can inspect to document their claim. Warren was skeptical that many EPA inspectors would be in the field scrutinizing company records, "given EPA's enforcement record these days."

EPA is drawing up guidelines detailing how firms can qualify for exemptions, and is developing a list of industries that probably would qualify for an exemption. But beyond those efforts, the agency has not developed any sort of inspection structure or enforcement strategy.

Firms that are not on the exempted list would have to determine whether their processes are releasing PCBs into the environment, and how much. EPA has specified the test that will be used.

However, under the proposal, manufacturers would not have to actually monitor their pollutants. They can, instead, conduct "theoretical assessments" of their processes to figure out the expected level of PCB releases.

Currently, the allowable level of PCBs in the air and water is 50 parts per million, but industry has argued that that is too low, and environmentalists think that the level is too high. EPA is expected to tell the court in November what standard it intends to use. In the meantime, firms with levels above 50 parts per million are expected to ask EPA for waivers.