NEW: Request of Comments on the Draft Chlorpyrifos Special Registration Review Scoping Document

The MDA is seeking public comments on the Draft Chlorpyrifos Special Registration Review Scoping Document (PDF) for 60 days, ending on September 17, 2020. Chlorpyrifos is a pesticide widely used in Minnesota to manage a variety of arthropod pests. Chlorpyrifos is also a source of contamination in multiple surface water bodies in Minnesota and can pose a substantial risk to human health and the environment. As of June 2020, 13 surface water bodies in Minnesota were proposed for designation by the Minnesota Pollution Control Agency (MPCA) or designated as impaired by the EPA due to chlorpyrifos water quality standard violations. In 2012, the Commissioner of Agriculture designated chlorpyrifos as a “surface water pesticide of concern.” Chlorpyrifos exposure can lead to acetylcholinesterase (AChE) inhibition and neurodevelopmental effects in humans. Thus, the Commissioner of Agriculture has directed the Pesticide and Fertilizer Management Division to conduct an in-depth special registration review of chlorpyrifos. 

To begin the chlorpyrifos special registration review, the MDA has drafted a scoping document in collaboration with the MPCA, Minnesota Department of Health, and the University of Minnesota. The Draft Chlorpyrifos Special Registration Review Scoping Document (PDF) defines the focus and topics of the review.

Following the 60-day public comment period, the MDA will consider all appropriately submitted public comments and publish a revised scoping document. The revised scoping document will be used to guide the review.

Written comments may be submitted on or before September 17, 2020 by e-mail to:

Theresa Cira (
MDA Pesticide and Fertilizer Management Division

The full State Register announcement can be viewed at the Minnesota State Register website (Volume 45, Number 3). Questions and/or requests for more information may be e-mailed to:

Theresa Cira (, or

Raj Mann (
MDA Pesticide and Fertilizer Management Division

Chlorpyrifos is a broad-spectrum insecticide used on agricultural crops, nursery plants, ornamentals, wood structures, cattle, and other habitats in Minnesota. It can also be used in greenhouse and nursery production, wood products, and roach bait stations. Most chlorpyrifos products are restricted use pesticides (RUPs). Applicators must be certified or licensed by the MDA to use products carrying the RUP designation.


Pesticide Type Insecticide (Group 1B)
Chemical Class Organophosphate
Common Trade Names* Warawk, Pilot, Chlorpyrifos 4E AG
Registration Status EPA: Registered since 1965
MN: Registered
diagram of chlorpyrifos chemical structure
*No endorsement is implied in the referencing of trade names.

The MDA created the webinar video “Chlorpyrifos Use in Minnesota” for applicators, farmers, and agricultural professionals which provides information on proper use of chlorpyrifos, label requirements, soybean aphid control, and pyrethroid-resistant soybean aphids.

Chlorpyrifos has been detected in surface waters in Minnesota through the MDA’s Ambient Water Monitoring Program and is currently designated as a “Surface Water Pesticide of Concern.” Select water bodies in the state have also been listed as “impaired” due to elevated detections of chlorpyrifos. The MDA has developed water quality best management practices and increased education and outreach efforts focused on chlorpyrifos.