EPA ensures that each registered pesticide continues to meet the highest standards of safety to protect human health and the environment. These standards have become stricter over the years as the ability to evaluate the potential effects of pesticides has improved. Therefore, the Agency has embarked on several programs to reevaluate pesticides as the standards evolve.

The Previous Process: Reregistration

Based on amendments to the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), in 1988 EPA was authorized to conduct a reregistration program. Reregistration was “a comprehensive review of the human health and ecological effects of pesticides first registered before November 1, 1984, to ensure that they met current scientific and regulatory standards.”1 Of the approximately 1,150 pesticide active ingredients reviewed, over 700 were reregistered by September of 2008, and the rest were canceled either voluntarily or because they didn’t meet new scientific and regulatory standards.

Chlorpyrifos, first approved in 1965, completed its reregistration in 2006 with all current agricultural uses reauthorized.

The Current Process: Registration Review

You can provide input into the registration review process for chlorpyrifos.

In 2006, just prior to the completion of the reregistration program, EPA initiated a new, ongoing program called “registration review.” Every 15 years, every pesticide active ingredient registered in the United States will undergo a formal reevaluation of its potential risks to human health and the environment. EPA describes the goal of the program as, “to make sure that as the ability to assess risks to human health and the environment evolves and as policies and practices change, all pesticide products in the marketplace can still be used safely.”2

Chlorpyrifos in one of the first major pesticides to be reviewed as part of this new program. Its registration review began in 2009 and is expected to be completed by 2015. You can view the registration review schedule for chlorpyrifos.


1. United States Environmental Protection Agency site. “Pesticide Reregistration Facts.”

2. United States Environmental Protection Agency site. “Reevaluation: Review of Registered Pesticides.”