Imprelis Ban Raises Questions about EPA OversightAug 15, 2011 | Parker Waichman LLP
DuPont's Imprelis herbicide, blamed for causing damage and death to thousands of evergreen trees in Minnesota, Michigan, Indiana, Ohio, Pennsylvania, New Jersey and Wisconsin, was finally banned by the U.S. Environmental Protection Agency (EPA) last week. While the ban is good news, many are wondering how a product so damaging to trees was ever allowed on the market to begin with.
DuPont marketed Imprelis, which was only available to licensed turf management professionals, as an environmentally friendly way to eliminate broadleaf weeds. Approved last October, DuPont's promises induced landscapers throughout the country to switch to Imprelis this spring. According to The Columbus Dispatch, industry sources estimate that in central Ohio, for example, 75 percent of landscapers and golf courses switched to Imprelis.
By Memorial Day, reports began to crop up around the country of tree damage that followed Imprelis application. In June, several extension services issued warnings about Imprelis. The damage was extensive, with Ohio landscaper Mark Wehinger telling the Dispatch that Imprelis e was lawn-care industry's Hurricane Katrina. Wehinger, a partner in the Dublin, Ohio lawn-care company Environmental Management, estimated that the herbicide has killed more than 1,000 of his customers' trees.
Most landscapers were pretty sure the problems they were seeing - yellowing, browning and curling o new growth, as well as massive needle loss - was the result of their use of Imprelis.
"The only thing that changed this year was the Imprelis, so we're confident that is the sole reason we have some of the damage,” Devon Stanley, maintenance-division manager of Benchmark Landscape Construction in Plain City, Ohio, told the Dispatch.
Extension services reached similar conclusions, with Ohio State University issuing a bulletin that stating that "a common denominator of this particular damage on these samples appears to be ... Imprelis."
By August 4, DuPont announced it would voluntarily stop selling Imprelis, and was working on a refund and return program for its customers. Last Thursday, the EPA issued a stop sale order for the herbicide, after data provided by DuPont confirmed that certain coniferous trees, including Norway spruce, white pine and balsam fir, were susceptible to being damaged or killed by the application of Imprelis.
So how did something so destructive make it to the market in the first place? According to a report from “Insects in the City,” a blog published by the Texas A&M Extension service, products like Imprelis are tested on a variety of tree species and under a variety of conditions, but not on all species under all conditions. As a result, problems with these types of products often don’t become apparent until they have been on the market for months.
According to a report published by The New York Times last month, the EPA reviewed Imprelis for 23 months before granting it conditional approval, meaning that all of the safety data was not yet in but the agency judged Imprelis to be a good product. DuPont says Imprelis went through about 400 trials, including tests on conifers, and performed without problem.
Unfortunately, it's not unusual for such testing to miss big problems. “Testing for all products continues even after a pesticide has been registered and sold,” according to "Insects in the City." To some extent, “real world testing is always going to be more comprehensive and rigorous than the pre-registration screening process.”