The U.S. EPA has released preliminary human health and ecological risk assessments for seven organophosphate pesticides (OPs). The preliminary risk assessments show risks of concern to agricultural workers and bystanders as well as dietary (food and water) risks of concern, and we expect to see similar risk concerns in the assessments for the other OPs, which will be issued for public comment over the next couple of years.

These seven pesticides – dimethoate, dicrotophos,* chlorpyrifos-methyl, tribufos, terbufos, profenofos, and ethoprop – are among the first organophosphate insecticides for which preliminary risk assessments have been completed under EPA’s registration review program. Used widely in agriculture, OPs act by inhibiting the action of an important enzyme in nerve cells. They can cause both short- and long-term effects.   

Agency scientists retained the FQPA 10X safety factor because of uncertainty in the human dose-response relationship for neurodevelopmental effects. EPA is soliciting comments from the public on both its position paper in support of the use of the FQPA 10X safety factor for each individual organophosphate human health risk assessment and the risk assessments themselves. That position paper is included in the docket for each OP. See Table 2 of the Federal Register Notice for the docket number for each organophosphate.

This week EPA Administrator Gina McCarthy, with Labor Secretary Tom Perez, announced updates to the Worker Protection Standard to protect the nation’s two million farm workers and their families from pesticide exposures.  At the same time, evaluating the safety of individual pesticides for workers continues to be an EPA priority. These risk assessments are an important step toward improving protection of our farmworkers as well as ensuring the safety of our food supply. 

EPA has phased out many of the OP residential and some agricultural uses over the past 15 years, thereby reducing the potential for exposure. The preliminary risk assessments for these seven OPs show that, although many uses have been eliminated, further mitigation measures or other restrictions may be necessary. If EPA determines that there are risks to workers from the use of these OPs, the agency will take action to reduce or eliminate those risks as part of our registration review.

Comments will be accepted until November 24, 2015.

*EPA previously solicited public comment on draft human health and ecological risk assessments for dicrotophos. Based on comments received, additional data and new science policies, we have revised the dicrotophos risk assessments and are releasing them again for public comment.