In a comment posted Oct. 14, the National Association of State Departments of Agriculture expressed concern that the atrazine restrictions would significantly increase weed pressure and risk forcing farmers to abandon no-till in exchange for deep tillage to control weeds.

The proposed rules would reduce the concentration equivalent level of concern equivalent from 15 parts per billion to 3.4 parts per billion, reduce atrazine usage to a maximum of 2 pounds per acre per year, prohibit aerial spraying, and ban atrazine applications to saturated soils, as well as within 48 hours of forecasted heavy precipitation.