The nonprofit environmental law firm Earthjustice has sued the Environmental Protection Agency (EPA) for failing to properly take into account the health and ecological risks of approved pesticides.

"There are several pesticides on the market that pose extreme risks to human health - through the water, air and food," said Earthjustice attorney Joshua Osborne-Klein. "Our lawsuits say that the EPA has not fully assessed these risks."

Of particular concern is the tendency of pesticides and other agricultural chemicals to end up in the groundwater, via air, soil and surface water contamination. The EPA has warned that groundwater is "highly susceptible to contamination from septic tanks, agricultural runoff, highway de-icing, landfills, and pipe leaks."

A 2006 report by the U.S. Geological Survey (USGS) found pesticide residue in every single stream tested, along with more than 50 percent of shallow wells and a third of deeper wells.

Although the EPA has directed states to address the issue of groundwater contamination, it has provided little guidance as to how this is to be accomplished, said Janet Fults of the Oregon Department of Agriculture's pesticides division.

"There are so many pesticides that do not have benchmarks," Fults said. "The EPA expects states to address water quality issues without benchmarks."

Only three states - California, New York and Oregon - have comprehensive pesticide reporting programs, and few states have conducted tests for water contamination. In Oregon, the Department of Agriculture found seven pesticides that regularly turned up. One of these was diazinon, which was originally developed as a lethal nerve gas and has been shown to pose serious health risks to children. The EPA banned its residential use in 2004, but still allows its agricultural use.

Earthjustice has filed suit over diazinon's continued use, noting its regular detection in surface water and in the air near schools.

"Children are really at risk," said Wenonah Hauter, executive director of Food and Water Watch. "And a lot of these pesticides aren't just found in groundwater; they're also found in food products."