Thursday, April 18, 2013

Persistent Herbicides Contaminating Animal Manures Making them "Killer Compost"

As an organic gardener, I'm concerned about the increased use with inadequate labeling of persistent herbicides such as picloram and clopyralid.  To read more on this issue, see this excellent article from Mother Earth News.

If you want to take action as suggested in the article, you could send an email to the EPA at this address:

Here is a letter that I wrote to the EPA that you may use as a template.  I'm sure you all can tailor it better.

Mr. Keigwin,

I am an organic gardener who is trying to garden vegetables at home to improve the health of my family and reduce our environmental impact by eating very locally.  I was surprised recently to learn that I can no longer compost horse manure to reuse as a fertilizer for our garden as it may be contaminated with persistent herbicides such as picloram and clopyralid.  Since these herbicides can persist through the animal ingesting the sprayed food product, get into the manure, and even remain after composting, they may still be present in the composted manure.  It is so sad that we as a country are allowing a potentially reusable resource like animal manures to become contaminated with herbicides that make it into a true waste product rather than a reusable resource.  These herbicides are too harmful to our farming cycle to continue to be legal.  I hope the EPA will change its policy toward these herbicides.



  1. 4/19/13 I received this email response from at the EPA:

    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 us again if you have additional questions.

    Danielle Miller
    Communication Services Branch
    Field and External Affairs Division
    Office of Pesticide Programs
    U.S. Environmental Protection Agency

  2. On 4/19/13 I replied back to Danielle Miller at the EPA:
    Ms. Miller,

    Thank you for your prompt response. I appreciate hearing all the things the EPA is doing to address this problem. There are a number of specific instances that I would like the EPA to consider. Currently I do not see how stronger labeling will help these possibilities. They are:
    1) I am involved with an organic community garden at a county park. The county park is a multi-use park, including hikers, bicyclists and horseback riders. The rangers of the park clean up the horse leavings from the trail and have developed an environmentally friendly approach to this waste - they compost it on site and use it on the park grounds and offer it for use to the organic gardeners. What a wonderful resource! Except it isn't! The manures from various horses recreating in the park could easily be contaminated, so this compost could kill the plants we are all hoping will benefit from the compost. Even if the herbicides are properly labeled, will the food products made from the crops be labeled? Will the manure on the trail be labeled?
    2) I used to stop at a local stable to get horse manure to compost at home. I can't do this anymore. So what had been a resource is now a toxic waste product.
    3) I've search for other manure sources to compost but most animals (e.g. chickens, rabbits) that I've found locally are bedded in straw or fed hay that could be contaminated. Again, more toxic waste and less of a good resource. Don't we already have enough trouble with animal waste from feedlots and such? Why add to the burden in this way?
    4) In the past, I've re-used the compost from a mushroom farm when they are done with it - they leave it piled in an enormous pile about 2 stories high and larger than a warehouse. This compost they make using, among other things, stable leavings of straw and manure from the local racetrack. Again, this source is no longer safe. More toxic waste is being generated rather than keeping the food chain free of these herbicides and therefore useful to farmers and gardeners.