Daily News Archive
From March 6, 2002
Bans Herbicide on Lawns
The Washington Department of Agriculture has banned the use of the herbicide clopyralid, produced by Dow AgroSciences, on lawns and turf because of concerns of the herbicide contaminating compost. The herbicide has been found in compost made from recycled grass, straw, and manure in California, Washington, Pennsylvania, and New Zealand.
The Washington state ban is initially in effect for 120 days, beginning March 1, 2002. At the end of the four months, the department plans to make the ban permanent and will consider additional restrictions on the use of the herbicide.
"This ban is meant to keep clippings from grass that has been treated with clopyralid from being sent to municipal and commercial compost facilities," said Cliff Weed, manager of the Pesticide Compliance Program for the Department of Agriculture. "We focused on grass clippings because they are the major source of contaminated materials."
Clopyralid, the active ingredient in Confront, kills broadleaf weeds such as dandelions, clover and thistles and has been registered for use in Washington state since the late 1980s. Evidence has been growing that when clopyralid-tainted compost is used to enrich soils, it can harm certain flowers, such as asters and sunflowers. Damage also has been found with vegetables, such as beans, peas and tomatoes.
The new restrictions make products containing clopyralid "state restricted use" pesticides when labeled for use on lawns and turf, including golf courses. This means they can be sold only by licensed dealers and bought only by licensed pesticide applicators. Clopyralid products will still be able to be used on golf courses if no grass clippings, leaves or other vegetation are removed from the site and sent to composting facilities that provide product to the public.
"These restrictions are our first step in resolving compost contamination issues," Weed said. "We'll continue to work on the issue with our stakeholders and advisory committee." For the past four months, Weed has led an advisory committee involving the agricultural community, composters and government regulators.
Clopyralid's persistence, mobility in soil and water solubility allows it to seriously damage plants. Clopyralid is toxic to sunflowers, tomatoes, potatoes and legumes at levels of 10 parts per billion (ppb). Residue testing of compost at the facilities revealed clopyralid levels between 73 and 80 ppb. These levels have the potential to damage crops, gardens and nurseries. The resulting occurrence of revenue losses, claim settlements, testing and additional labor cost one facility at the University of Washington $250,000.
The herbicide is popular with many crop farmers and commercial lawn-care companies. Compost companies receive about 28 million tons of yard trimmings each year. Clopyralid does not break down during the commercial composting process. It remains lethal up to 18 months after initial use.
Unless the herbicide is eliminated, compost and recycling companies told the Los Angeles Times that their businesses could go bankrupt. "You cannot have a system that mandates recycling of green waste and license a garden chemical that makes the waste unrecyclable," said Gabriella Uhlar-Heffner, solid waste manager for Seattle's public utility company.