Washington state bans clopyralidThis, from the Washington State Department of Agriculture website: "Effective March 1, 2002, herbicides containing the active ingredient clopyralid may not be used on lawns and turf in the state of Washington. The purpose of the ban is to keep clopyralid, a long-lasting herbicide, from potentially contaminating compost. The ban is initially in effect for 120 days. By late June, the department plans to make the ban permanent and will consider additional restrictions on the use of the herbicide.
"Golf courses are exempt from the ban as long as no grass clippings, leaves or other vegetation are removed from a course and sent to a composting facility that provides product to the public."
For more information, go to the Washington Dept. of Agriculture website.