California environmental officials Wednesday banned the sale of lawn care products containing the weedkiller clopyralid.
The decision, effective in 30 days, comes after testing indicated that compost made at as many as 75 of California's 100 green-waste recycling facilities may be contaminated by the chemical.
The weedkiller, made by Dow AgroSciences, is not toxic to human or mammals, and is used to kill clover, dandelions and thistles. It gets into compost when clippings from treated lawns are put in green-waste bins for curbside collection, then taken to state facilities for recycling. The grass is broken down into compost and sold to farmers, landscapers and home gardeners.
The product has been viewed as wholesome enough to be used as a soil conditioner for organic growers.
But in 1999, compost tainted with clopyralid began killing "nontarget" vegetables, including petunias, daisies, tomatoes and potatoes in Pennsylvania and Washington state. Washington State University scientists traced the problem to products containing clopyralid.
Since then, testing revealed contamination in 90% of the state's compost. On March 1, the Washington State Department of Agriculture responded with an emergency ban on use of the chemical in lawn-care products.
A week later, the Sonoma-based California Quality Compost Coalition, a trade association of green-waste recycling companies, reported only slightly less sweeping contamination of compost in California: 13 of 20 sites tested showed a trace of the chemical. In Southern California, both the San Diego and the Los Angeles Bureau of Sanitation have been reporting positive tests since June. Both city governments are now warning customers that their compost may be contaminated.
Stephen Grealy, San Diego's recycling program supervisor, welcomes the ban. "I think that's an excellent first step," he said. "But there are many composting facilities in California that also receive agricultural waste."
Grealy warned that even with swift removal of the product from store shelves, it will take time to clean up compost. "We will still see a lingering problem because of the residual activity, I expect, for many months to come."
A spokesman for Dow AgroSciences said the company was caught off guard by the announcement.
"We will be getting back to Department of Pesticide Regulation in the near future with a more detailed response," spokesman Garry Hamlin said.
The weedkillers affected by the ban include:
* The Andersons Lawn Fertilizer (Tee Time 18-5-9 With Millennium Ultra Herbicide, United Horticultural Supply Professional Turf Products 22-3-4 With Millennium Ultra, the Andersons Professional Turf Products 16-4-8 With Millennium Ultra Herbicide & PCSCU).
* Dow AgroSciences LLC (Lontrel Turf and Ornamental, Lawn Fertilizer Plus Confront Weed Control, Turf Fertilizer Containing Confront, Confront).
* Howard Johnson's Enterprises Inc. (Howard Johnson's Weed & Feed With Millennium Ultra).
* Lebanon Chemical Corp. (Lebanon Proscape Homogeneous Fertilizer With Confront Herbicide Broadleaf Weed Control).
* Lesco Inc. (Lesco Momentum Premium Weed & Feed).
* Monterey Chemical Co. (Millennium Ultra Selective Herbicide).
* Riverdale Chemical Co. (Riverdale Millennium Ultra Selective Herbicide, Riverdale Millennium Ultra Weed and Feed, Riverdale Trupower Selective Herbicide, Riverdale XRM-5202 TM Premium Weed and Feed).