Persistent Herbicides: USCC History
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Persistent Herbicides: A Long-Term fight


In the wake of the Chittenden County disaster and revelations, the USCC organized a Persistent Herbicide Task Force. The Task Force developed the Position Statement, a work plan, and coordinated efforts to impact the herbicide re-registration process of the three most common persistent herbicides, Clopyralid, Picloram and Aminopyralid.

Examples of the impact of our work on Capitol Hill in 2014 anda 2015:

Direct question to EPA Administrator McCarthy by US Representative Serrano (D-NY) at the House Budget Hearing
(Questions to Ms. McCarthy appear at approximately 1:45)

Letter to McCarthy from Representative Nolan (D-MN)

Response to Rep. Moran (D-VA)


Thanks to the pressure of USCC members and allies, USCC then-President Frank Franciosi and then-Executive Director Michael Virga, along with Brenda Platt, then Chair, USCC Legislative & Environmental Affairs Committee and Dr. Fred Michel, Ohio State University, met with the Environmental Protection Agency (EPA). Representatives from EPA included Dan Kenny, Branch Chief, Herbicides Branch and Lois Rossi, Director, Registration Division, and representatives from the Pesticide Re-Evaluation Division, the Environmental Fate & Effects Division and the Biopesticides & Pollution Prevention Division.

Concerned stakeholders from Vermont, Pat O’Neill, Director, Composting Association of VT, Tom Moreau, General Manager, Chittenden Solid Waste District and Cary Giguere, Pesticide Program Section Chief, Agrichemical Management Section, Vermont Agency of Agriculture participated in the meeting via telephone to offer their thoughts and experiences.

Some of the outcomes from the meeting include:

·       EPA confirmed continued support for composting and the composting industry and put a priority on investigating the Vermont incident.  They are currently on the ground and working with Dow, Dupont and the Chittenden Solid Waste District.  Dow and Dupont are involved in a review of methods to analyze contamination.  EPA will decide on the appropriate action, pending the outcome of its investigation.

·       EPA and USCC agreed to form a task force to develop a test method to prescreen herbicides for fate-in-compost that will involve experts from both organizations.  Will Brinton (Wood End Lab), Assaf Sadeh (Soil Control Lab), Fred Michel (OSU), and Al Rattie (Former USSC Director of Market Development & STA) were designated to work with EPA on developing the fate-in-compost testing protocol.   These chemicals are up for re-registration in 2014.

·       EPA said they needed to know if the Vermont incident was a stewardship issue, a labeling issue, or a misuse issue.  Dan Kenny stated that EPA needed to have a very clear understanding of the source of the compounds that are proving problematic in Vermont before they take any actions on labeling requirements.

·       Two things under discussion included setting up a confidential complaint hotline to report incidents regarding herbicide-contaminated compost and a funding source for composters to defray the cost of remediation for the damage done by these compounds.  Funding for both of these items was proposed to be the responsibility of Dow and Dupont.


(August, 2012)

Green Mountain Compost, owned and operated by Chittenden County Solid Waste District, Williston, Vermont, suffered a devastating discovery—something in their compost was causing garden plants to distort and wither!  The culprit? A couple of pernicious, persistent herbicides called clopyralid and picloram.  This after investing $2.3 million in a state-of-the-art facility designed to recover food waste, yard debris and agricultural wastes from Burlington and the surrounding area.  How did these herbicides, which have negligible recorded licensed use in Vermont, get there?  They were probably used on a hay field somewhere to control weeds, the hay was fed to horses, the horses’ manure was sent for composting along with other materials, and the finished compost had traces of the herbicides in sufficient strength and amount to cause damage.  It takes VERY little to kill many garden plants, as little as 10 parts per billion.  That is like 1 drop diluted in an Olympic sized swimming pool.

Clopyralid and picloram are examples of a relatively new class of herbicides called pyridine-carboxylic acids.  Others include aminopyralid and triclopyr.  It is clear that regardless of what Dow, DuPont or others put on their labels or try to control their use, they can eventually end up in compost and then in plants that can and will be harmed.  All pesticides have to pass a variety of tests before the EPA will register them for use.  Tests include toxicity (such as to humans and fish), carcinogenicity, and other potential health and safety issues.  They DO NOT include a compostability test.  But with the continuing growth of the composting industry, more and more potentially tainted materials will end up in compost, leading to the type of results Chittenden County is experiencing.

Unfortunately problems with persistent-herbicide-contaminated compost are not new or unique to Vermont. Ten years ago clopyralid contamination shut down the compost facility in Spokane, WA. Compost contamination problems have been documented since then in California, Idaho, Minnesota, New Jersey, North Carolina, Ohio, Pennsylvania, and Washington.  It’s time for federal action.

USCC called on the EPA to add a “compostability test” to its registration requirements, and set a compostability standard for all chemicals that could potentially end up in a composting facility.  We are confident that if the companies had to meet such a standard, they could and would.  But if it is not a requirement, nothing else will compel such a change.

USCC further urged EPA to (1) immediately initiate a Special Review Process for all herbicides that are pyridine-based compounds and act by mimicking plant growth hormones (auxins), and (2) impose a moratorium on the use and sale of these herbicides pending the conclusion of the Special Review Process.  EPA uses the Pesticide Special Review process when it has reason to believe that the use of a pesticide may result in unreasonable adverse effects on people or the environment. The Special Review process involves evaluating existing data, acquiring new information or studies, assessing the identified risk and determining appropriate risk reduction measures.