EPA Reverses Ban on Chlorpyrifos


Courtesy of UL - The WERCS

The United States Environmental Protection Agency (EPA) has announced that it is not yet ready to ban the use of chlorpyrifos on food crops, despite growing concerns from lawmakers and members of the public regarding its safety. The chemical – which is an organophosphate insecticide – is primarily used to control foliage and soil borne insect pests on food and feed crops.


Chlorpyrifos was introduced in 1965 by Dow Chemical Company, and has been used as a pesticide for both food and non-food purposes to control pests such as aphids, armyworms, beetles and various types of mites. It is sold under many brand names including Lorsban, Andersons Golf Products, Eraser, Warhawk, Duraguard, Cheminova, Drexel, and Helena Chemical.

In agriculture, chlorpyrifos is most commonly used on corn, although it is also used on soybeans, fruit and nut trees, Brussels sprouts, cranberries, broccoli and cauliflower. Non-food application of the chemical includes use on golf courses, turf, greenhouses, and on non-structural wood treatments such as utility poles and fence posts.

Chlorpyrifos is considered moderately hazardous to humans by the World Health Organization. At high enough doses, the chemical can cause cholinesterase inhibition (i.e. overstimulation of the nervous system), which can cause nausea, dizziness, and confusion, and at very high exposures it can result in respiratory paralysis and even death.

Restrictions on the use of Chlorpyrifos

Use of chlorpyrifos on certain food crops has been limited in recent years. To address health and environmental risks from its exposure, the EPA have placed a number of restrictions on pesticide products containing chlorpyrifos:

  • In June 2000, chlorpyrifos was eliminated from all homeowner uses, except ant and roach baits in child resistant packaging and fire ant mound treatments. In the same year, the substance was also banned for use on tomatoes, and limited to pre-bloom and dormant applications on apples
  • In 2002, chlorpyrifos use was limited on citrus, tree nuts and other crops
  • In 2012, “no-spray” buffer zones were created around public spaces, including recreational areas and homes

Despite these restrictions, chlorpyrifos is still in wide use for a variety of other food crops such as corn, cabbage and strawberries, and widespread use for non-food purposes continues.

What is the current position on Chlorpyrifos?

In 2015, under the Obama administration, the EPA proposed a full ban on chlorpyrifos. However, on March 29th 2017 EPA administrator Scott Pruitt – appointed by the Trump administration – overturned the EPA revocation, and denied a subsequent petition by environmental groups that sought to ban the pesticide.

The EPA says that it will continue to study the chemical, and like other pesticides, chlorpyrifos must undergo a regular registration review every 15 years to “ensure it will not cause unreasonable adverse effects when used according to label directions and precautions, and that there is a reasonable certainty of no harm from dietary and residential exposure”.

The statutory deadline for the next review of chlorpyrifos is October 1st 2022. It does not appear that the EPA intends to take any further action at this stage.

Is any other action being taken?

As a result of the EPA’s reversal, other action regarding chlorpyrifos is underway. At the Federal level, Democratic senators have recently introduced a bill to ban the chemical, whilst at State level, Mississippi has already limited its use in certain crops, and does not allow aerial application.

California has also recently put temporary restrictions on its use. The State is currently performing reviews that may lead to restrictions on how and where chlorpyrifos is used, and this may potentially lead to its inclusion as a Prop 65 substance known to cause birth defects or other reproductive harm.

The California Department of Pesticide Regulation (DPR) has released a draft evaluation of chlorpyrifos as a toxic air contaminant, and comments are being accepted on this document until October 2nd 2017. If you would like to submit a comment, you can do so by emailing chlorpyrifos@cdpr.ca.gov.

In addition to this, the DPR will be holding a public workshop on September 15th 2017 to discuss the draft evaluation at the Pesticide Registration and Evaluation Committee meeting in Sacramento. More details on this event can be found here.

The Developmental and Reproductive Toxicant Identification Committee (DARTIC) of the California Office of Environmental Health Hazard Assessment’s (OEHHA’s) Science Advisory Board is also discussing this pesticide and taking comments on this up until October 16th 2017 in preparation for discussion at their next meeting. The public can make oral comments at the DARTIC meeting on November 29th 2017 (at the California EPA in Sacramento), provided they limit their comments to 5 minutes or less. Longer comments can be made with advance approval, and requests to do so must be made by October 30th 2017 to P65Public.Comments@oehha.ca.gov or by calling (916) 445‑6900.

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