Proposed U.S. Ban on Endosulfan May Be Its Exit Cue

Used around the world against aphids, beetles, and other pests for more than half a century, endosulfan appears to be on the way out. Citing health risks for farmworkers and wildlife, the U.S. Environmental Protection Agency (EPA) announced yesterday that it is "taking action" to end all uses of endosulfan in the United States, where it has been allowed for restricted use on tomatoes, cotton, and other crops.

Already banned in more than 60 countries, the organochlorine pesticide acts as a neurotoxic compound in humans and has impacts downstream on fish and other creatures, according to studies reviewed by EPA. Data included in one of EPA's recent environmental risk assessments showed it is present in some streams at levels high enough to kill fish.

In 2002, EPA called for more data from the registered manufacturer (Bayer at that time) during scheduled product re-registration. Reports of negative impacts heated up the review in 2007, and EPA called for public comment, which came from growers, nonprofit environmental groups, and the registrants. EPA evaluated the pesticide's risks and benefits under the Federal Insecticide, Fungicide, and Rodenticide Act and released an updated risk assessment yesterday.

Research not connected to this review has shown that the pesticide is persistent, bioaccumulative, and toxic--three characteristics that qualify it for evaluation under the Stockholm Convention as a possible "ecotoxicological" agent. The international treaty went into effect in 2004; participants have banned the use of persistent organic pollutants (POPs) that travel across the planet, by air and by sea, starting with the so-called Dirty Dozen (DDT included). Like these chemicals, endosulfan also tends to show up in places far from original application sites, including the Arctic.

Last year, the scientific body advising the Stockholm Convention decided that endosulfan qualifies as a POP. While the United States participates only as an observer in the Stockholm Treaty, the U.S. EPA's decision to phase out endosulfan at home may create waves abroad. The agency's press materials released yesterday underscore endosulfan's persistence, bioaccumulative potential, and toxicity. "If the U.S. does it, other countries will reexamine their policies," says Karl Tupper of Pesticide Action Network North America, a nonprofit group that has signed on for past lawsuits against the use of the pesticide and participates as an observer at Stockholm Convention meetings.

The U.S. phaseout will depend on the position of the current registrant, Makhteshim Agan of North America. In 2007, Bayer voluntarily stopped selling endosulfan in the United States; it will stop globally by the end of the year. Tupper, who sat in on a stakeholders' meeting yesterday, says that EPA reported it will negotiate with Makhteshim Agan over the next 3 weeks to establish a timetable for phasing out the pesticide's use.