Where It Comes From
Applied to corn, soybeans, sorghum, peanuts, and other crops; rain and irrigation can carry it into streams and groundwater [1][3].
How You Are Exposed
Drinking water (especially private wells in farming areas), residues on food, and skin or breathing it during mixing/spraying at work [1][3].
Why It Matters
Short-term exposure can irritate eyes/skin; higher doses harmed liver and kidneys and affected development in animal studies. Evidence for cancer in humans is inadequate (IARC Group 3) [1][2][3].
Who Is at Risk
Pesticide applicators and farmworkers; residents near treated fields; people using private wells; infants, children, and pregnant people [1][3].
How to Lower Your Exposure
Check your water quality report; test private wells if you live near fields; consider NSF-certified activated carbon or reverse osmosis filters; wash produce; and follow label PPE and re-entry times [3][4].
References
- [1]U.S. EPA. Reregistration Eligibility Decision (RED) for Metolachlor. EPA 738-R-95-006 (1995).
- [2]IARC Monographs, Volume 73: Metolachlor. International Agency for Research on Cancer (1999).
- [3]U.S. EPA. Metolachlor/S-metolachlor: Human Health Draft Risk Assessment for Registration Review (2018).
- [4]U.S. EPA. Drinking Water Treatability Database: Metolachlor (accessed 2025).