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Thank you for writing to express concerns to the Environmental Protection Agency about herbicide residues in compost.

I apologize for the delay in responding.

The EPA is working with pesticide registrants, the U.S. Composting Council and other stakeholders to address concerns about persistent herbicides finding their way into mulch or compost. We are also looking into the potential for contaminated compost to damage or kill non-target plants. We have been pursuing several different paths to investigate and address these concerns.

First, the agency has been working with state agencies to help determine the cause of compost contamination, where it has been detected, and to develop the best methods for detecting and analyzing residues in compost.

We are also working to strengthen product labeling for these herbicides. We have added stronger advisory language and additional use precautions and restrictions on grazing, haying and using plant residues or manure. In addition, the agency has been working with the registrants to build a stewardship program involving education and training. The program will involve tracing the source of contamination, holding parties responsible and educating them on the correct use of the products. The agency will continue to evaluate all of the information that it receives to determine whether additional mitigation is necessary on these types of chemicals.

Another path the EPA is using to address compost concerns is a workgroup to discuss designs for developing standardized testing for pesticides that could persist in composted material. The workgroup consists of representatives from the U.S. Compost Council, the California Recycling Council and the State Federal Insecticide, Fungicide, and Rodenticide Act Issues Research and Evaluation Group. SFIREG is a network of state officials interested in federal/state "co-regulation" of pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act.

Finally, the agency’s ongoing Registration Review program is designed to address concerns that arise for pesticide products that are already registered. Under the Registration Review program, the agency periodically reviews registered pesticides to make sure they meet the statutory standard for registration; that is, each pesticide can still perform its intended function without posing unreasonable risks to human health or the environment. The EPA will consider the issues associated with contaminated compost and manure as we assess and develop decisions for these herbicides. We encourage interested members of the public to participate in this open, transparent process. For information about the registration review status of particular herbicides of interest,

please see the 

Schedule for Beginning Registration Review, 2012-2015 

or look up the chemical’s regulatory status on 

EPA’s Chemical Search.

I hope you find this information useful. Please write to us  if you have additional questions.

Danielle Miller:

Communication Services Branch

Field and External Affairs Division

Office of Pesticide Programs

U.S. Environmental Protection Agency

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