Composting Program

Clopyralid

Clopyralid, an herbicide produced by Dow AgriScience designed to kill broadleaf weeds such as clover, thistle, and dandelions; is used by professional lawn care providers. Concerns arose in Washington state when compost produced from tainted grass clippings were found to damage sensitive plants such as beans, peas, and tomatoes.

In 2002, DEQ, working with the Oregon Department of Agriculture (ODA), conducted a three-phase study which sampled “for sale” compost at 30% of DEQ permitted facilities. The initial tests showed clopyralid residuals at levels of concern at all sites. Subsequently, in July, 2003, ODA restricted use on residential lawns, commercial and public turf plantings, school grounds, parks, and recreation centers. Follow-up testing over two years showed a decline in clopyralid to very low levels.

• Fact Sheets
• Publications
• News Release: Oregon Department of Agriculture - January 19, 2005 PDF
• Permanent Rule: OAR 603-057-0378
  (This link will take you to the Oregon State Archives web site.)
• Oregon Department of Agriculture Restricts Use of Clopyralid
  July 23, 2003 News Release, Request Phone: 503-986-4635

Other Clopyralid Information:

• California Assembly Bill on Clopyralid
  Search for AB 2356, 2001-2002 Session.
• California Integrated Waste Management Board
• Washington State Department of Agriculture
• US Composting Council Position Paper on Clopyralid and Composting.

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