Robert Taylor fought for years for stronger limits on the toxic chemical released by a neoprene factory in his Louisiana parish. Last year, the Biden administration finally delivered some relief, publishing a rule to reduce hazardous air pollutants from petrochemical plants.

Now, Taylor fears that hard-fought gain will vanish before it is realized.

Last month, chemical industry groups sent a letter to the Environmental Protection Agency seeking a broad, two-year exemption for any facilities covered by the regulation. The request came in response to an EPA offer to consider exemptions to new air pollution rules that covered nine industries, including chemicals, power plants and metal manufacturing.

Last month, after the EPA said it was reconsidering a host of regulations issued by the Biden administration, the agency opened the door for companies to seek exemptions under a clause of the Clean Air Act. The provision allows the president to issue waivers to rules if he or she “determines that the technology to implement such standard is not available and that it is in the national security interests of the United States to do so.”

Parts of Louisiana known as “Cancer Alley,” which includes St. John the Baptist Parish, have some of the highest concentrations of these pollutants. One study published last year by researchers at Johns Hopkins University found ethylene oxide levels up to 1,000 times higher than what the EPA considers an “acceptable risk.” The levels were up to 20 times higher than what EPA estimates suggested.