EPA will continue to allow widespread use of the weed killer atrazine despite evidence that it has contaminated certain drinking water systems at levels 12 times greater than allowed by law. EPA recently completed an assessment of atrazine, the most heavily used herbicide in the United States, finding that numerous communities have dangerous levels in their water. Yet the agency ignored calls for a ban on the product -- which studies have linked to cancer in both humans and animals -- and instead entered into an agreement with Syngenta, the largest manufacturer of atrazine, under which the company itself will perform increased testing of raw water entering community water systems where atrazine is used. Syngenta already monitors water for atrazine, yet nearly 200 community water systems, serving more than 3.6 million people, have shown levels of atrazine close to or above the legal limit. "We're flabbergasted," "http://www.nrdc.org/media/default.asp#0131atrazine">said Jennifer Sass, a senior scientist at the Natural Resources Defense Council (NRDC). "We've reviewed the science on atrazine, and it is clear that it is dangerous at levels the EPA says are harmless." EPA performed its assessment of atrazine, which is used mainly on corn, sugarcane and residential lawns, as the result of a lawsuit filed by NRDC.