(CNN)Drug cartels illegally growing marijuana on federal public lands in California are getting bolder and using banned, toxic pesticides, officials said Tuesday.
Use of federal lands for illegal pot a growing concern, California officials say
The secret marijuana sites are organized, funded and operated by Mexican cartels, said US Attorney McGregor Scott. The issue is particularly stark in California, which has more than 16 million acres of national forest lands, including Yosemite, Kings Canyon and Lassen Volcanic National Park.
"This is not a bunch of people growing marijuana in the woods," Scott said in a news conference Tuesday. "This is people who are using chemicals and causing manifest environmental damage to a crown jewel of the United States -- our federal public lands."
The illegal growers divert the water supply, use toxic chemicals banned in the US and clear native plants and trees, in order to grow marijuana plants on what were pristine federal lands.
The issue of illegal marijuana farms on public lands has persisted in California for years, but Maj. Gen. David Baldwin of the California National Guard said they had seen a "tremendous uptick and increase in the amount of environmental damage and degradation that's done by the growers, that have become bolder and bolder to take the public lands."
One of the major concerns is the widespread use of toxic and illegal pesticides, which pose dangers to the environment, wildlife, water supply and human health.
One of the pesticides detected at the illegal sites is carbofuran, which is banned in the US on all crops grown for human consumption. The toxic pesticide can seep into soil and streams, killing plants, wildlife including threatened species, and affecting humans who hunt and consume the animals.
Tests found that 78% of the illegal marijuana grow sites had signs of carbofuran.
Federal, state and local officials pledged to work together on this issue with $2.5 million of funding from the US government. "Our national parks and forests are priceless treasures ... but these assets are being destroyed by criminal organizations that cultivate millions of marijuana plants on these lands each year for profit," Scott said.
The US Forest Service estimated that about 1.4 million illegal marijuana plants were found in California last year. Many of these marijuana sites are located in rural counties where there are vast stretches of US forest land.
"We've been besieged in recent years," said Siskiyou County Sheriff Jon Lopey. "We're absolutely overwhelmed."
The growers also tend to be armed, which could be dangerous for visitors to public lands. Some of the growers claim to be affiliated with Mexican drug cartels such as the Sinaloa cartel and Jalisco Nueva Generación, said Bill Ruzzamenti, director of the Central Valley California High Intensity Drug Trafficking Areas program.
They leave behind plastic pipes, irrigation lines, tools, human waste and other garbage in what had been undisturbed habitats, according to the US Attorney's Office for the Eastern District of California, which shared a photo from one of the sites.
"In addition to the poison and waste, the cultivators divert water to the marijuana plants, drying up streams and reservoirs used for plants, animals and humans," it stated.