Persistent Herbicides and Compost Don’t Mix
Share |

Photo Courtesy of Chittenden Solid Waste District

Persistent Herbicides and Compost Don’t Mix

Compost is an amazing tool for breaking down herbicides and all sorts of other problematic chemical compounds.  Given the right mix of bacteria, fungi, and the conditions they need to thrive, otherwise dangerous compounds are often rendered inert in a surprisingly short timeframe.

This is not the case with persistent herbicides.  Much has been written about the disastrous effects when these resilient compounds make their way into a compost pile.  For the past two decades, they’ve been causing big problems for composters throughout the U.S. and beyond.

In 2012, Green Mountain Compost, a program of Chittenden Solid Waste District (CSWD) of Williston, Vermont, suffered significant losses following the discovery of Aminopyralid (one of the more potent persistent herbicides widely used for agriculture) in the compost we sold to customers.  CSWD incurred close to a million dollars in losses responding to and compensating more than 500 customers whose gardens were affected.  Were it not for significant financial support from the municipality, the compost operation likely would have been shuttered.  This experience paved the way for a greater understanding of how to recover from an incident of persistent herbicides at a compost facility.

Some improvements have been made since the incident seven years ago. However, usage of these compounds has not slowed down and the risk of contamination at compost facilities is very real and likely to get worse.  Aminopyralid is not currently marketed in the northeast, but it can still be purchased through online platforms and will be going off patent in January of 2021 (meaning greater availability to consumers and likely less product stewardship from producers).  The options for lab testing compost and manures for persistent herbicides are more limited than they were even a few years ago.  Incidents continue to occur nationwide, but they are underreported due to the potential stigma associated with the compost products.  

So what’s to be done?  The family of compounds known as persistent herbicides represent billions of dollars to the agriculture industry.  In order for the composting industry to achieve greater protections in the future, the U.S. EPA needs to know that this is a significant problem for our industry.  This starts with reporting incidents whenever they occur.  If you suspect you have had an incident involving persistent herbicides in your compost contact the USCC (link below) and your state pesticide control officials. Many of the persistent herbicides of greatest concern are also up for reregistration and review at the EPA in 2020. Join the USCC in our effort to exert more protections for composters by submitting comments.

USCC Persistent Herbicide Reporting Form
USCC Persistent Herbicide Factsheets
USCC Persistent Herbicide FA

Dan Goossen is the Director of Composting at Chittenden Solid Waste District (CSWD) of Williston, Vermont. Dan began his compost career at Intervale Compost Products (renamed Green Mountain Compost) in 2003 and has been the General Manager for the past eleven years. Dan has presented regularly on persistent herbicides in compost as well as many other topics ranging from compostable plastics to overwintering beehives in Vermont.