Long after illegal marijuana gardens cultivated on public lands have been cleared, the trash, toxic chemicals and other environmental damage remain.
"They've terraced, they've filled garbage pits, they've contaminated the ground with various chemicals," some of which have been banned in the United States, said Gary Sharpe, associate field manager with the Bureau of Land Management's Ukiah office. His office's jurisdiction includes two of the state's top five pot producing counties, Lake and Mendocino.
Poaching and stream diversions also are problems, he said. "I don't think people realize how much damage they do," Sharpe said.
"They" are believed to be mostly Mexican nationals working for drug cartels back home. The hired laborers live in makeshift camps on public lands during the outdoor marijuana growing season.
When they leave, or are chased off by the law, left behind are mini-landfills, toxic pools of water, animal carcasses and miles of drip irrigation pipe.
Of the 2.9 million pot plants seized during the state's 2008 Campaign Against Marijuana Production, 70 percent were on public land. The figures do not include year-around pot seizures by other federal, state and local law organizations.
Local officials also have been dealing with toxic messes left on private property.
Lake County's public lands are hot spots of marijuana cultivation. The county has been tops in the number of seized plants during CAMP operations for the past three years. The program yielded almost 500,000 plants in 2008, most of them from public lands.
BLM law enforcement officials estimate it costs $1 to $2 to eradicate each plant and four times that to clean up the mess left behind by growers, Sharpe said.
"We could easily go though $1 million a year for the next five years" to clean up what's already been left on BLM lands, he said. "And that's if (the pot cultivation) stopped. Which it's not going to do."
Nor is sufficient funding available.
BLM received $20,000 last year for a pilot cleanup project during which it removed garbage from two gardens along the Lake-Mendocino border with the help of volunteers and their pack horses, Sharpe said.
It expects to get another $95,000 this year, with $75,000 for cleanup on two former pot gardens in the Cow Mountain area.
The U.S. Forest Service does not receive money specifically for pot garden cleanups, but the California division set aside $350,000 of its budget to clean up 30 sites in California, said Ron Pugh, special agent in charge of law enforcement in California.
Officials locate about 350 such sites a year, he said.
"Most haven't been cleaned up," Pugh said. He's hoping legislators will increase allocation for the efforts.
Marijuana legalization proponents say the problem would be alleviated if marijuana was legalized, which they say would reduce the monetary incentive to grow illegally.
The pot garden cleanups are costly because the refuse -- fertilizers, pesticides, rodent poison, propane tanks, food, human waste, tarps and plastic tubing -- is widely scattered in remote regions. It must be consolidated into piles that are then either hauled out or picked up by helicopters.
Illegal pot production has become the U.S. Forest Service's national priority, Pugh said. Congress has voted to double the number of its law enforcement officers to 160, he said.
Twenty of those are dedicated to marijuana eradication and tracking down the people who head the operations, Pugh said.