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Illegal marijuana growers are poisoning national forests with banned pesticides

REUTERS/Rafael Marchante
Keep it clean.
Published This article is more than 2 years old.

Over the past month, US law enforcement has uncovered some 25,000 marijuana plants growing illegally within California’s national forests, according to federal court documents reviewed by Quartz. In at least one case, the illicit growers sprayed the plants with one of the most dangerous pesticides in the world. 

Known as carbofuran, the pesticide is banned for poisoning humans and killing wildlife.

“These are federal lands, and they are being systematically destroyed through clear-cutting, stream diversion, chemicals and pesticides,” a federal prosecutor told reporters on Tuesday (Aug. 20). “It’s a vitally important issue.”

For years, carbofuran, sold under the brand name Furadan by Philadelphia-based FMC Corporation, was sprayed on American corn, cotton, potatoes, sunflowers, and other food crops. Regulators took carbofuran off the American market in 2008 after it was blamed for killing more birds in the US than any other pesticide in history. It is also banned in the European Union, Canada, and more recently, Brazil

Numerous studies have found that the pesticide disrupts the endocrine system in lab animals, interfering with reproduction. The material safety data sheet for carbofuran warns that exposure could cause “blurred vision, tearing, pin-point pupils, blue skin color, convulsions, tremor and coma,” among other acute responses.

In 1998, in Fresno County, California, 34 farm workers were sickened after going to work on a cotton field recently sprayed with carbofuran, according to a UC Centers for Disease Control report. Meanwhile, the EPA estimated at the time that carbofuran was killing 1 to 2 million birds in the US each year. More recently, 13 bald eagles were found dead on a farm in Maryland in 2016, felled by ingesting carbofuran.

The pesticide is poisonous enough to kill a fully-grown bear with a single teaspoon, notes the Los Angeles Times. In 2008, the BBC reported that in Kenya, carbofuran was being used by herders to kill lions that threatened their herds. A vulture expert in Kenya told the BBC that 187 vultures died within minutes of feeding on a single carbofuran-laden carcass. “I literally saw vultures dropping out of the sky,” he said.

But despite the ban, carbofuran continues to plague California. It is the pesticide of choice for illegal pot growers, found at nine out of every 10 illegal pot farms discovered by law enforcement last year, according to the Associated Press. In 2016, authorities in California advised citizens to “wash” their weed after cops found carbofuran at an illegal grow site.

The chemical has already contaminated thousands of acres of forest and seeped into streams, threatening animal and human health in the state. In some cases, responding law enforcement officers have been hospitalized after touching plants or equipment. Environmental groups, meanwhile, are struggling to decontaminate the many illegal grow sites that used carbofuran. As of August 2018, workers had cleaned 160 toxic sites, but 830 more still await cleanup. And those are only the ones they know about.

Environmentalists, scientists, and at least some government officials, have a simple solution: Legalization.

Less secrecy, more sunlight

A 2015 study by scientists and researchers at the nonprofit Nature Conservancy, the California Department of Fish and Wildlife, and the University of California Berkeley, argued that the “clandestine nature of the business…encourages secrecy and invisibility among producers for both the semi-legal medical and black markets, leading to lower levels of voluntary compliance with existing environmental regulation.”

The semi-legal status of marijuana, which remains prohibited under federal law, also impedes the associated study of any environmental impacts, and hampers the “creation and implementation of solutions,” the study said, which viewed the issue through a purely environmental lens.

Accordingly, it concluded, reducing environmental harm and enforcing environmental laws are the paramount aims, “regardless of the legal status of marijuana.”

“Inherent trade-offs and tension between marijuana cultivation and ecosystem needs exist, as they do in virtually all types of agriculture,” it said, “and those tradeoffs should be quantified and debated openly, as they are in other industries.”

Federal busts

On Aug. 9, agents with the US Forest Service (USFS) flew a helicopter over the Sierra National Forest in California, looking for illegal weed grows. They found one near Dutch Oven Creek, a protected wilderness area, where growers tended to between 5,000 and 7,000 plants.

The unit watched the area for 10 days. And then, on the morning of Aug. 19, it raided the grow. After a brief foot chase, agents apprehended two of three suspects. One got away. Back at the site, they found something familiar.

“One bottle of carbofuran, a hazardous pesticide that is banned in the United States, was located in the cultivation site,” according to a Forest Service affidavit. “Additionally, a backpack sprayer containing suspected carbofuran was located and it appeared the carbofuran had been applied to the marijuana plants.”

Federal agents have dismantled at least six other outlaw marijuana farms on public lands in Northern California recently. And while none of the court filings specifically mention carbofuran, all say the operations are using toxic pesticides or fertilizers without any supervision or monitoring.

“I suspect that many of the cases are awaiting laboratory confirmation since we typically find carbofuran in re-purposed bottles,” wildlife biologist Mourad Gabriel told Quartz. “Therefore the lack of mention until a definitive ruling is generated.”

  • On July 26, agents and officers from the California Department of Fish and Wildlife raided an illegal grow deep within the Stanislaus National Forest. The operation turned up 2,642 marijuana plants and one loaded handgun. One suspect was arrested. The site was not far from another illegal grow that was busted by local authorities last year.
  • On July 31, law enforcement discovered more than 11,000 marijuana plants growing illegally near Crocker Mountain in the Plumas National Forest. Filings related to the case don’t mention carbofuran specifically, but say there were “over the counter” bags of fertilizer found at the scene.
  • On Aug. 2, Forest Service agents, along with officers from the California Department of Fish and Wildlife and the Fresno County Sheriff’s Office raided an illegal grow operation carved out of federal lands in the Sierra Nevada mountain range. They seized 2,448 marijuana plants and a loaded AR-15 rifle.
  • On Aug. 8, the feds raided an illegal grow in a remote part of the Mendocino National Forest and found 906 marijuana plants. They had kept the site under surveillance since May, according to court filings, which say agents observed the crew trucking 50-lb. bags of fertilizer, among other things, to the site. Two suspects were arrested and charged.
  • On Aug. 13, agents raided a second site in Mendocino National Forest, seizing 741 illegally-grown marijuana plants. The suspects were linked to the ones arrested in the Aug. 8 operation, according to court filings.

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