EPA’s draft report on the ecological assessment of the herbicide atrazine sparked concern from pesticide makers and farm groups.

Atrazine is one of the most widely used agricultural pesticides in the United States. It is used primarily on corn, sorghum and sugarcane to control broadleaf and grassy weeds in the Midwest. Atrazine increases crop yields and enables no-till farming and conservation tillage, which help keep aquatic systems healthy by dramatically reducing soil runoff into rivers and streams.

“More than 7,000 scientific studies have found atrazine to be safe,” says Maryland farmer Chip Bowling.

Chip Bowling, president of the National Corn Growers Association., says over the last 50 years, atrazine has passed some of the most rigorous safety testing in the world. “More than 7,000 scientific studies have found atrazine to be safe,” Bowling says.

NCGA expressed concern that EPA has chosen to base the ecological risk assessment for atrazine on studies their own Science Advisory Panel deemed “flawed” just four years ago. “This undermines public confidence in the review process and goes against the mission of using the best available science,” Bowling says.

Syngenta says the assessment contains “numerous data and methodological errors and needs to be corrected.”

Marian Stypa, Ph.D., head, product development for Syngenta in North America, says the draft assessment discounted several rigorous, high-quality scientific studies and didn’t adhere to EPA’s own high standards. “The draft report erroneously and improperly estimated atrazine’s levels of concern for birds, fish, mammals and aquatic communities that are not supported by science.”

For example, data presented in the 2012 SAP demonstrated the level of concern (LOC) for atrazine could be more than six times higher than the conservative number proposed in EPA’s preliminary report, and still be protective of aquatic communities. Together with numerous errors in EPA’s modeling, the agency drew scientifically unsound conclusions, based on flawed assessments that need to be corrected.

“Assessments, even ones that are drafts, with such far-reaching consequences should only be based on the best, highest quality science to ensure farmers have this critical and irreplaceable tool for U.S. agriculture,” says Vern Hawkins, president, Syngenta Crop Protection, LLC, and North America region director. “We’re confident that when given a thorough science review, atrazine’s continued, longstanding safety will be confirmed.”

A 2012 University of Chicago economic study reported farming without atrazine would cost corn growers up to $59 per acre. While corn prices have fallen since the report was released, the availability of atrazine for use in corn could make the difference between growers making a profit or incurring a loss on their crop, Syngenta cited.

“That’s a cost many farmers cannot afford, and it would have ripple effects across the entire food and agriculture sector,” Bowling says of the study.

“Syngenta looks forward to EPA reviewing public comments, using the best available data, and correcting and revising the draft risk assessment. We also look forward to the SAP on atrazine in 2017,” says Hawkins.