Last week, we reported that the National Clean Air Coalition had claimed 312 major industrial plants in 39 states were polluting the air with dangerous and cancer-causing chemicals, endangering millions of Americans. The coalition said its evidence came from a little-known 1980 EPA study that the coalition publicized now because Congress is considering relaxing the Clean Air Act.

Well, EPA says its report was inaccurate. Several of the plants that the coalition identified as polluters do not even emit the cancer-causing chemicals it cited. Another plant hadn't used the dangerous substances cited in the report since 1960.

The U.S. Chamber of Commerce immediately accused the coalition of "misinterpreting scientific findings." And David R. Patrick, EPA's director of pollutant assessment, said the coalition had taken the report "a little out of context." Patrick said he wrote a letter to the Sierra Club, which belongs to the coalition, pointing out that the report was "very preliminary" and should not be cited as factual.

"We didn't have the time or money for a thorough study, so the report was based on literally any data available: telephone calls to companies, state agency reports, and even pure guesswork," Patrick said in an interview. "The final report contained 20 pages of explanations about how uncertain the figures were. Everyone, including the coalition, realized the report was a rough, ballpark estimate."

Coalition spokesman David Doniger says his group knew the report contained "speculative data" but, he said, twice during 1981, EPA had distributed copies to the industries involved, seeking corrections.

"While there have been maybe 100 to 120 challenges of pollutant figures in the report , that still leaves several thousand of the pollutant figures unchallenged," said Doninger. "We still believe the plants are emitting 2 1/2 billion pounds of pollutants per year and we want EPA to do something about that." Doninger said his group will soon issue its own corrected version of the EPA data.