Sacramento, Calif. — Nine of every 10 illegal marijuana farms raided in California this year contained traces of powerful and potentially lethal pesticides that are poisoning wildlife and could endanger water supplies, researchers and federal authorities said Tuesday.

That's a jump from chemicals found at about 75 percent of illegal growing operations discovered on public land last year, and it's six times as high as in 2012.

Federal and state officials launched a summer-long crackdown driven in part by new concern over the increase in the use of the highly toxic pesticide carbofuran.

Researcher Mourad Gabriel, one of the few researchers studying the ecological impact of illicit grow sites, said the pesticide is so powerful that a quarter-teaspoon can kill a 300-pound (136-kilogram) bear.

He and fellow researchers at the Integral Ecology Research Center in northwestern California found 89 percent of sites this year have been confirmed or are strongly suspected to be contaminated with what he called "highly deadly toxic chemicals."

The crackdown aided by $2.5 million in federal money led to 95 growing sites and the removal of more than 10 tons of fertilizer, pesticides and chemicals.

U.S. Attorney McGregor Scott said federal authorities are concentrating their efforts on hazardous illegal grows on public land instead of targeting California's new recreational marijuana industry.

 
"This isn't about the marijuana, it's about the damage that's being done," he said in an interview before a news conference to announce the findings. "What is happening here is illegal under anybody's law."

California Attorney General Xavier Becerra, who leads the nation's largest marijuana eradication program, said state drug agents last week found gallons of carbofuran being added to irrigation water at an illegal site in northwestern California. The water ultimately makes it into the water supply in a rugged, mountainous area near the city of Redding.

Investigators suspect some illegal grows are now being moved into agricultural areas where they blend in alongside legitimate marijuana and other crops. For example, they raided two illegal marijuana farms south of Sacramento this summer based on information on a cellphone found at an illegal grow in the Mendocino National Forest last year, Scott said.

To learn more of these harmful pesticides that are harming our wildlife, visit their website here.