Facing a wide-scale ban in California, the maker of a highly potent weedkiller asked the federal government Friday to ban the use of its own product by homeowners across the country.
The action by Dow Chemical subsidiary Dow AgroSciences would remove lawn care products containing the weedkiller clopyralid from the shelves of hardware stores and garden centers nationwide.
The request, made to the U.S. Environmental Protection Agency, would not prevent professional lawn care companies, or even local gardeners, from applying the chemical to residential lawns, nor would it keep it off the grass at cemeteries, schools, parks and other public spaces.
Dow spokesman Garry Hamlin said the company decided to request the residential restrictions after discussions with the EPA about problems with clopyralid residues on grass left for pickup by curbside collection programs. This grass then was turned into garden compost at municipal recycling centers. Finished compost made from grass treated with clopyralid has proved toxic to some common garden plants.
Dow AgroSciences Vice President Erin Miller described the move as "a prudent step" while scientists studied the decomposition of the chemical in compost.
Sponsors of a California Assembly bill calling for tighter restrictions dismissed Dow's move as window dressing.
"Dow is trying to put itself in the role of a responsible citizen," said Stephen Grealy, recycling program supervisor for San Diego. "But in effect what they are trying to do is undercut legislation that would go a lot further to cure the problem. Half of the lawn in California is commercial lawn, and that's where most of it is used. Dow is only removing it for sale for treatment of residential lawn."
The chemical, which was approved by the EPA in 1987, is sold in all 50 states under as many as 37 brand names, such as Confront, Stinger and Lontrel. It is a favorite of lawn care companies because it kills dandelions, thistles and English daisies but spares grass. A little bit also goes a long way: One application lasts a year, where rival products may have to be applied two or three times a year.
However, by 1999, clopyralid's persistence had been identified as a problem by Dow and university researchers. Unlike other garden chemicals, it did not break down when cut grass was sent for recycling into compost. Soil scientists from Washington State University traced deaths of "non-target" but sensitive plants--such as tomatoes and petunias in nurseries and community gardens--to compost made from grass clippings from treated lawns.
Further cases of contamination were subsequently recorded in New York, Ohio, Pennsylvania, New Zealand and Canada. In Pennsylvania, the clopyralid residues were so potent that compost made from leaves that had fallen on treated lawns was contaminated.
In California, which only licensed the chemical in 1997, grass recycling facilities in San Diego and Los Angeles recorded the first positive tests for clopyralid last year. By February of this year, the California compost industry estimated that as many as two-thirds of the state's facilities had some sort of contamination.
Municipal compost sold in Los Angeles and San Diego comes with warnings that it may kill common garden vegetables.
The pervasiveness of positive tests prompted the California Department of Pesticide Regulation to issue an emergency ban in February. This seems to have worked, according to recycling supervisors in San Diego and Los Angeles. After a series of positive tests at two Los Angeles facilities earlier this year, "everything has been coming up clean, clean, clean," said Stephen Fortune, the principal sanitary engineer at the Bureau of Sanitation.
San Diego now is getting clean tests, and elsewhere in the state, in hard-hit counties such as Sonoma, green-waste recyclers report that clopyralid contamination levels are falling steadily.
However, the recycling community--a mix of local governments and private contractors--also has turned to lawmakers. Last spring, it lobbied for an Assembly bill banning almost all turf use of the chemical. The measure has been approved by the Assembly, and its sponsors expect the state Senate to follow suit this summer.
Meanwhile, in Washington state, where the chemical has been most heavily used, state and city officials said almost all of the compost tested is positive, and readings are routinely five to 10 times higher than in California. The worry is that clopyralid contamination will end the market for municipal compost and bring down entire green-waste recycling programs developed in the last 10 years.
The Spokane Regional Solid Waste System said Monday that it plans to close its 72-acre Colbert compost facility because of clopyralid contamination.
The facility that once composted 40,000 tons of yard waste a year has been unable to take in this season's clippings because of a backlog of unusable compost tainted by the chemical. The authority plans to buy out the contract of the operator of the Colbert facility for $950,000 and close the site, in spite of millions of dollars invested in it. "We don't wish to be owning the land or be in this business anymore," said Damon Taam, system contract manager for Spokane Regional Solid Waste System.
The authority also is considering suing Dow.
"It is an option that we're exploring," Taam said. "We've obviously had a significant amount of damage here."