OAKLAND — The company that owns Messalonskee Dam will face a penalty from the state after an employee was caught spraying a toxic weed killer in and around the water.

The amount of the herbicide Durazone sprayed Aug. 3 by an employee of Essex Hydro Associates, the parent company of Messalonskee Stream Hydro, was small, according to Maine’s Board of Pesticides Control. Durazone in large amounts can cause severed effects in humans and animals.

Henry Jennings, the board’s director, said the tiny amounts of toxin detected after the spraying were unlikely to have any meaningful environmental consequences. He said the net effect was putting a half-ounce of herbicide into the lake. “It’s going to quickly get below the biologically active level,” he said.

Durazone, sold by Bayer, kills a wide variety of plants, and contains the active ingredients indaziflam, diquat dibromide and glyphosate isopropylamine salt. Its label warns it’s toxic to plants, fish and other aquatic animals. The National Pesticide Information Center says prolonged or extreme exposure by humans can cause severe health effects in humans, from shedding fingernails to spontaneous late-term abortions.

“To protect the environment, do not allow pesticide to enter or run off into storm drains, drainage ditches, gutters or surface waters,” its label reads.

Jennings said that chemical warning labels are legal documents that applicators are federally required to comply with.

The Board of Pesticides has one full-time investigator and four seasonal investigators, who together handle about 600 investigations a year, Jennings said. Because of the high volume of cases handled by the small staff of the board it could take months to determine what the penalty will be.

“We’re confident that some enforcement is appropriate, but we haven’t arrived at exactly what that would be,” Jennings said. “Clearly education is a part of it. The company needs to have a better understanding of the applicable laws.”

Jennings said Essex Hydro Associates is cooperating and the incident appears to be isolated.

Oakland resident Ed Pearl, a former director of Friends of Messalonskee Lake, was driving by the dam when he saw the man spraying Durazone on plants growing in spillway boards used to impound water on the north end of the lake. He confronted the man and later filed a complaint with the state board, triggering the investigation.

While most are routine inspections of places where pesticides are used commercially, Jennings said that the board also responds to about 100 complaints every year.

“We rely on the public to be our eyes and ears,” he said.

Messalonskee Stream Hydro also owns three projects in the Kennebec River system and the Benton Falls dam on the Sebasticook River.

If the company has to pay a fine, the money goes to the state’s general fund. Jennings said that helps ensure that the enforcement agency doesn’t benefit by assessing high fines.

Matt Hongoltz-Hetling — 861-9287

mhhetling@centralmaine.com