DuPont to recall, stop selling herbicide Imprelis

DuPont said it plans to stop selling and recall its widely used Imprelis herbicide (active ingredient: aminocyclopyrachlor) after customers and several lawsuits complained that the treatment has killed thousands of trees.

In a statement on Thursday, DuPont said it is in talks with the U.S. Environmental Protection Agency on "the most effective way to implement our recommendation of a voluntary suspension of sale of DuPont Imprelis herbicide, and a product return and refund program."

It said the talks are intended to "assure full transparency of important scientific data" regarding Imprelis.

The EPA conditionally approved Imprelis for sale last October, but DuPont this year began receiving many complaints that the herbicide may be lethal to mature landscape trees.

DuPont has since advised customers, including professional landscapers and golf course owners, not to use Imprelis near Norway spruce and white pines.

DuPont, based in Wilmington, Delaware, is one of the world's biggest chemical companies, with $31.51 billion of net sales in 2010.

It has not broken out sales for Imprelis, but its agriculture business, which includes herbicides, typically accounts for nearly one-third of net sales.

The EPA on Wednesday wrote letters to DuPont Chief Executive Ellen Kullman in which it strongly encouraged the company to release thousands of confidential documents on Imprelis' safety and effectiveness.

It also encouraged DuPont to meet with the agency by next Tuesday to discuss a possible halt to Imprelis sales.

The EPA is preparing a "stop sale" order, a person familiar with the matter said. The source requested anonymity because of a lack of authority to speak publicly on the probe.

Wednesday's letters were written by Abraham Ferdas, director of the EPA's land and chemicals division, and posted on the agency's website.

On its own website, DuPont has called Imprelis "the most scientifically advanced turf herbicide in over 40 years," targeting broadleaf weeds such as dandelion, clover, plantains, wild violet and ground ivy.

It said the product went through more than 400 trials and was approved for use in all U.S. states except California and New York.