https://phys.org/news/2018-05-toxic-pesticide-illegal-california-pot.html

Researchers found the highly toxic pesticide Carbofuran at 72 percent of grow sites last year, up from 15 percent in 2012, said Gabriel, executive director and senior ecologist at Integral Ecology Research Center and one of the few researchers studying the ecological impact of illicit grow sites.

California has long allowed medicinal marijuana and legalized recreational pot this year. While U.S. Attorney McGregor Scott will enforce federal laws that ban the drug, he said he is targeting illicit grows on public land with cooperation from California's attorney general and the state's National Guard.