Clopyralid in Compost
Clopyralid is the common name of a herbicide that kills broad-leaved weeds such as dandelions, clover, and thistle. Clopyralid contamination of yard debris compost emerged as a problem in Washington State in 2000 and 2001. Clopyralid has since been banned as a lawn herbicide, removing the risk of contamination of yard debris compost. Because clopyralid is still registered for use on grass hay and some grain crops, the risk of contamination of some animal manures with clopyralid remains.
♣ WSDA Rule Restricting Use of Clopyralid in Washington (see WAC16-228-1235, WAC16-228-12351, WAC16-228-12352, 16-228-1237, 16-228-12371 (link to WSDA main website).