Syngenta Crop Protection Inc. agreed last week to settle a class-action lawsuit out of court rather than go to trial over claims related to the herbicide atrazine. The settlement could help some utilities in Iowa cover the cost of removing the chemical from drinking water.

Atrazine is banned in the European Union but remains one of the most common herbicides used in the U.S., especially by corn growers. Unfortunately, atrazine gets into groundwater, and its presence is correlated with breast cancer and prostate cancer. Another study found that mothers living near farms that spray atrazine were more likely to have babies with a certain birth defect, especially if the babies were conceived during months when most agricultural spraying occurs. Some research has implicated endocrine disrupters like atrazine in rising obesity rates.

The role of environmental chemicals in obesity has garnered increased attention in academic and policy spheres, and was recently acknowledged by the Presidential Task Force on Childhood Obesity and the National Institutes of Health (NIH) Strategic Plan for Obesity Research. “Over the past ten years, and especially the past five years, there’s been a flurry of new data,” says Kristina Thayer, director of the Office of Health Assessment and Translation at the National Toxicology Program (NTP). “There are many studies in both humans and animals. The NTP found real biological plausibility.” In 2011 the NIH launched a 3-year effort to fund research exploring the role of environmental chemical exposures in obesity, type 2 diabetes mellitus, and metabolic syndrome.

Removing atrazine from drinking water requires expensive equipment. Seeking compensation for those costs, a group of 16 water utilities in the Midwest sued Syngenta AG, a company based in Switzerland, and its U.S. subsidiary Syngenta Crop Protection Inc. The southwestern Iowa city of Creston was the only Iowa plaintiff, joining the class-action suit in 2010.

Syngenta has always claimed that current atrazine levels pose no threat to human health, but last week they agreed with plaintiffs’ attorneys to settle for $105 million. A statement from the corporation said the settlement would “end the business uncertainty,” adding,

This settlement is good for Syngenta and the farmers who depend on atrazine, as well as Syngenta’s retailers, distributors, partners, and others who have been inconvenienced by this ongoing and burdensome litigation for almost eight years.

Assuming a judge approves the settlement, Syngenta would admit no liability but would pay $105 million toward the cost of atrazine removal systems. The lead attorney for the plaintiffs, Stephen Tillery, said that 1,887 water utilities serving more than 52 million people may be eligible to make a claim.

The amounts eligible water systems may recover will depend upon the levels and frequency of atrazine contamination they experienced, as well as the population served by each of them, Tillery said. Some 300 water systems with the highest contamination levels will be reimbursed all of their costs, he said.

“The scope of this historic settlement is enormous and its protection of the health of millions of Americans across the country is a huge benefit to the public, the environment and the taxpayers,” Tillery said.

Under the tentative deal, attorneys representing the water systems will share roughly $34.9 million in fees.

The Environmental Working Group found in 2009 that 37 Iowa water utilities “reported detecting Atrazine in tap water since 2004.” Atrazine levels were highest in the water from Creston, followed by water from utilities based in Iowa City, Peterson, Osceola, Davenport, Chariton, Centerville, Greenfield, Lamoni, and Leon. The atrazine levels in Iowa drinking water were all lower than the U.S. Environmental Protection Agency’s maximum contaminant limit. Samples from nine Iowa water suppliers had atrazine levels above the public health goal set by the State of California Office of Environmental Health Hazard Assessment.

Peak concentrations of atrazine may be higher than average levels reported under current EPA regulations. The EPA has been evaluating the effects of atrazine on humans since 2009, but I doubt this process will lead to any new restrictions on the chemical’s use.