EPA to study whether Imprelis lawn weed-killer hurts trees

The U.S. Environmental Protection Agency is expected to begin an "expedited review" by the end of this month into whether the weed-killer Imprelis is harming or killing some species of evergreens, an EPA spokesman said.

"Once we receive investigative data (in the form of incident reports), which should be later this month, we will conduct an expedited review to determine if any changes in the use of the product are needed," said the spokesman at EPA headquarters in Washington who declined to be named as a matter of agency policy.

"EPA is taking this very seriously," he said. "It is still quite early in the investigative process."

The EPA has received reports from numerous states including Michigan that Imprelis, a new DuPont lawn herbicide touted as environmentally friendly, is suspected of damaging Norway spruce and white pine trees. The Free Press reported the problem a week ago, with experts estimating damage could reach into millions of dollars.

The Wilmington, Del.-based chemical company has urged landscapers not to apply Imprelis on properties where there are Norway spruce or white pine trees and told the Free Press it was conducting its own investigation. DuPont also has warned property owners not to use grass clippings treated with Imprelis for mulch or compost.

On July 6, the EPA held a teleconference discussing suspected incidents in Minnesota, Indiana, Illinois, Ohio, Michigan, Pennsylvania, Maryland, Virginia, Delaware, Wisconsin and West Virginia.

Incident reports are being collected from those states, and other states have been notified of the problem, the EPA said.

The EPA could take actions including:

• Requiring revisions to the label about the use of Imprelis.

• Requiring additional testing.

• Ordering Imprelis off the market.

Imprelis is not available to the public. Only licensed landscapers can purchase the herbicide.

"Right now, the agency cannot make a determination on whether Imprelis is directly responsible for harming trees, but we are working with the regions, the states and DuPont to learn more," the EPA said.