Wednesday, August 10, 2011

Persistent Herbicide

I am pretty sure that not many of you follow national compost news as closely as we do.

Recently, the big news has been the introduction of a persistent herbicide by DuPont. Imprelis (also Milestone and Forefront) contains a broad leaf herbicide, aminocyclopyrachlor, designed to withstand "wear and tear", as it were, and remain active for up to a year. This means that when sprayed on a lawn to end growth of broad leaf weeds such as dandelions, the active ingredient remains active, even after being composted, for up to a year or more. Most herbicides available to certified applicators and all those available to the general public are broken down by the microbial action that occurs during the commercial composting process. For this reason, Soilutions has never been worried about what chemicals our tipping customers use on the greenwaste we receive at our recycling facility. (10 years ago, Dow Chemical introduced a persistent herbicide containing the active ingredient clopyrlid. The US Composting Council, and several states quickly joined forces to demand that Dow remove it from circulation.)

After a story by the New York Times ( told of 1000's of people in the northeast experiencing die-back or death of certain conifers resulting from "misuse" of Imprelis, we began to followed the story more closely in the trade magazines. Because of the location of the events, and the fact that most use was on golf courses or municipal parks, greenwaste generators of which we don't see much, we were still not worried about it. Then a customer came to us claiming that he planted tomatoes in our soil and they were showing signs of herbicide distress, according to his nurseryman. (Never mind that the soil he bought this year was made two years ago before Imprelis was even on the market, nor that the other 1000 cubic yards of topsoil was getting its usual rave reviews.) The idea that there was toxic soil being sold in the area was becoming a stronger one and that would not do anybody in the business any good.

I called all the nurseries, shopped at the big box stores, checked all the labels of all the available herbicides and found not one contained the active ingredient of Imprelis. Our friends at Plant World, Inc even promised that if they were given the opportunity to carry it, they would decline. Then I called a chemical fertilizer manufacturer in Albuquerque. They do carry Milestone, but that turns out to be an insecticide and it is costly ($500+/gal), too costly to be widely used by our customers. Even they had not yet heard of Imprelis.

So this all happened in July and August. Just as I was writing the draft for this article, DuPont issued a "voluntary recall" of Imprelis and set up a website ( to assist those affected by its misuse. I was skeptical that they would cop to any wrong doing. It is registered with the EPA ( and there are specific restrictions concerning its use on page 9 (or some such)of the warning label booklet (who reads those things anyway?).

Just the next week, while browsing a discarded New York Times I noticed an article claiming that the EPA had banned the sale and use of Imprelis ( Score one for the EPA, the USCC,BioCycle and all the others that put pressure on the chemical giant.