New rules proposed to limit contamination in organic waste

Gardeners, landscapers, and homeowners all love compost. But no one loves the bits of plastic, paper - even glass - that sometimes get mixed in with commercially produced compost. That contamination is unsightly, potentially environmentally harmful, and can cause injuries to people and animals.

A new rule proposed by the Washington Department of Ecology is designed to limit contamination in compost, ensure that as much organic material as possible is recovered and work hand-in-hand with broader state efforts to keep food waste out of landfills. This matters because when food waste enters a landfill, it becomes one of the largest contributors to climate pollution in Washington.

Ecology is asking the public to review the proposed rule and submit public comments before the public comment period ends on Aug. 13, 2026.

Dealing with contamination is critical because the amount of organic material collected in Washington is expected to increase four-fold by 2035, according to a report released last year. The increase is being driven by a 2022 law requiring most local governments in Washington to provide residents and businesses food and yard waste collection services by 2030.

The law sets minimum standards for contamination in compost. To implement these standards, Ecology's proposed rules would set a universal limit on allowable levels of contamination in the material that comes into these facilities - and in the finished compost that goes out.

Peter Lyon, who manages Ecology's Solid Waste program, said that providing clarity around acceptable contamination levels is essential to successfully expand organics collection.

"When compost is contaminated with plastics and other materials, it reduces both the environmental and the economic value of that material," Lyon said. "When there is too much contamination, organic material that could be composted instead goes to the landfill. Setting standards for contamination will help prevent that and make sure that we're recovering and reusing as much organic material as we can."

The draft rule proposes setting a 5% by volume physical contamination limit on incoming loads of organic material used as feedstock. It also adds a section to establish new pre-processing standards to address loads contaminated above 5%. The proposed rule aligns with Washington Department of Transportation compost procurement standards by setting contamination limits in finished products to 0.5% by dry weight. Film plastic contamination cannot exceed 0.1%.

The public review and comment period for the Organic Materials Management rule is open until 11:59 p.m. on Thursday, Aug. 13, 2026. There are several ways to provide input:

Submit comments online: https://swm.ecology.commentinput.com?id=iPusYareb

Comment during one of two public hearings. Both events include a presentation, question and answer session, and an opportunity to provide comments. Register in advance at one of the following links:

Email your comments to Ecology or send them through the U.S. Postal Service.

• Email to: [email protected]
• Mail to:
  Chris Fredley
  Department of Ecology
  Solid Waste Management Program
  PO Box 47600
  Olympia, WA 98504-7600

After the public comment period ends, Ecology will consider all the information received and finalize the rule for adoption. More information is available at https://ecology.wa.gov/regulations-permits/laws-rules-rulemaking/rulemaking/wac-173-350.