Fifty Democratic lawmakers in Washington have put their names to a letter asking the Environmental Protection Agency to abandon changes to emissions rules for chemical recycling — changes that EPA Administrator Lee Zeldin and the plastics industry have themselves been pushing for.

The letter, dated June 18 and addressed to Zeldin, centers on pyrolysis, the heat-driven process that converts plastic waste into feedstock and that the industry has positioned as advanced recycling. At stake is how EPA regulates emissions from those facilities, and whether pyrolysis operations continue to face the current requirements or operate under looser rules favored by resin makers and processors investing in the technology.

Sen. Jeff Merkley, D-Ore., led the congressional push. He and 50 Democrats from the House and Senate signed the letter, which seeks to block the regulatory changes sought by the EPA administrator and the plastics industry. The letter follows earlier reporting by Plastics News that Zeldin has been pressing the agency to ease the regulatory treatment of chemical recycling.

For operators of pyrolysis facilities and the brands counting on chemically recycled content to meet recycled-content commitments, the rulemaking is a load-bearing piece of federal policy. The emissions framework determines permitting pathways, compliance costs and the pace at which announced pyrolysis capacity can move from project to plant.

The lawmakers' intervention signals that any rewrite of the emissions rules will not proceed unchallenged on Capitol Hill. A letter from 50 members of Congress carries no binding force — the EPA can proceed with a rulemaking regardless — but it establishes a documented opposition bloc and creates a paper trail that Democratic lawmakers can use in oversight requests, appropriations riders or future litigation support should the agency finalize the changes.

It also frames the fight in terms the industry has worked to avoid: emissions from chemical recycling, and the question of whether pyrolysis should be regulated as waste processing or as manufacturing. The plastics industry has argued that pyrolysis units handle material that has already been segregated for recovery and should be treated accordingly. Opponents counter that the thermal processes carry air-emission profiles that warrant the stricter controls now on the books.

Zeldin's EPA has sided with the industry's reading. The proposed changes would alter the emissions rules that currently apply to pyrolysis chemical recycling, easing the regulatory path for the sector. Merkley and the 49 other signatories want that effort stopped before it advances.

The material stream at issue is the hard-to-recycle fraction — mixed and contaminated plastics that mechanical recyclers generally cannot process economically and that chemical recyclers say only pyrolysis and similar technologies can capture at scale. How EPA classifies and regulates the emissions from processing that stream will shape investment decisions across the chemical recycling project pipeline in the United States.

What happens next depends on the EPA's formal rulemaking steps. If the agency moves ahead with the emissions-rule changes, the June 18 letter becomes the baseline of congressional opposition, and the comment period and any final rule date become the milestones to track. If the agency slows or withdraws the rewrite, pyrolysis operators keep operating under the existing emissions framework.