U.S. Revives Plan to Kill Marijuana With Paraquat

Times Staff Writer

The Drug Enforcement Administration has quietly resurrected a plan to spray the herbicide paraquat on marijuana fields throughout the United States. The herbicide program, part of a nationwide effort to eradicate illegal marijuana farms, could eventually involve the use of more than 300 tons of paraquat on an estimated 15,000 acres across the country.

The agency says the new proposal has been prompted by the rapid expansion of the marijuana industry in this country and the subsequent need for an efficient method of destroying plants after they have been discovered. The drug is now harvested by commercial growers in all 50 states, the DEA says, and its officers are limited to mechanical eradication techniques.

Unaware of the Plan

Although the new proposal has been described in a 200-page environmental review released by the DEA in May, officials of pesticide control agencies in California and several other states say they have not received copies of the review and were not aware that the plan existed until notified by a reporter. Nor, they say, were they invited to appear at a June public hearing on the proposal in Los Angeles.


“I’m surprised to hear about it,” said Robert Peterson, a special assistant to state pest management director Lori Johnston. “With an issue as sensitive as this one, I would think (the DEA) would let the affected parties know in advance.”

Paraquat is a controversial herbicide with a high toxicity that can cause death and injury to humans under some circumstances. Officials in California said they would resist the use of paraquat for marijuana eradication in this state because of the dangers to people and wildlife.

“If (the DEA) decides to go this route, we will be seeking guidance from our lawyers,” Peterson said. “We would have to examine our own requirements for a permit.”

OK in Georgia


Pesticide officials in Kentucky and Georgia--two other states that would be major targets of an eradication campaign--also said they had received no notification of the plan. Georgia officials said they had no objection to the use of paraquat; Kentucky officials said they did.

“We determined that our citizens are opposed to it and quite honestly we work for them,” said Capt. Charles Johnson, chief of the narcotics division of the Kentucky State Police.

Two years ago a previous attempt to use paraquat on hidden marijuana farms in Georgia met a torrent of criticism. The spraying, which took place briefly in the Chattahootchie National Forest, was halted by the courts on grounds that the herbicide was not approved for use on federal lands.

The new proposal involves eradication programs on what the DEA refers to as “non-federal” territory: state, Indian-owned and private lands. In an environmental assessment of the project, the DEA says about 87% of the illegal marijuana crop in this country is grown on such lands, with California leading the nation.

Different Approaches

The environmental review proposes several alternative approaches for eradication and disposal, and says no final recommendations have been made. Those recommendations are expected late this summer.

However, the environmental review describes the agency’s “preferred” approach. That approach would make available to drug enforcement officers a mixture of mechanical and herbicidal techniques that would be used at the officers’ discretion. In addition to paraquat, the preferred approach would also employ the herbicides 2,4-D and glyphosate.

Officials in all the states contacted said they would also want to review the use of those herbicides. However, they noted that both substances are far less toxic than paraquat and are likely to pose less danger.


Paraquat and its use as a marijuana killer has produced heated reaction since 1973, when the Mexican government began using the chemical to destroy marijuana in that country. Soon thereafter some tainted shipments of the drug arrived in the United States, giving rise to fears that users would be harmed by smoking it.

Results Were Mixed

Research into such dangers has yielded mixed results. The federal Centers for Disease Control in Atlanta has reported no documented cases of paraquat poisoning from tainted marijuana, but doctors there concede that victims might be reluctant to divulge their illness. Laboratory studies in the 1970s produced lung damage in rats who were exposed to smoke from marijuana saturated with the herbicide, leading to a warning by the National Institute for Drug Abuse that a danger did exist for people who smoked more than five tainted cigarettes a day.

Paraquat’s danger to people or wildlife exposed directly to the chemical is well documented. The product is manufactured in this country by Chevron Chemical Co., and the company’s own pamphlet warns: “Paraquat is highly toxic. One swallow can kill and the symptoms are prolonged and painful.” Death from paraquat is usually produced by pulmonary edema, or fluid in the lungs, and occurs three to four days after exposure.

There is little likelihood that inadvertent exposure would produce a fatal dose, but injury from drifting spray mist or contact with saturated vegetation is possible. In recent years, in fact, concern has centered on the exposure of people or wildlife who happen to be near marijuana eradication projects, rather than users of the drug. The effects from skin exposure are less serious than from swallowing but still can produce major illness, especially if the skin has been scratched or cut.

Meant for Other Weeds

In San Francisco, officials at Chevron Chemical Co. say the company has opposed the use of paraquat for marijuana eradication. The product is usually sold to farmers as a “pre-treatment” to rid fields of weeds before crops are planted. Paraquat has been tested for that purpose and a few others, the officials say; it has not been tested for marijuana eradication.

“In 1982 we said--because of the unknowns--that we would prefer our product not be involved,” said G. Michael Marcy, a spokesman for Chevron.


“We feel the same way now. But if the federal government is willing to conduct health and safety tests and if those tests prove beyond a shadow of doubt that this is a safe way to go, then we might be willing to talk about it.”

At the Drug Enforcement Administration, officials say they have no plans to conduct those tests because, they contend, past safety studies on paraquat are sufficient. Rodolfo Ramirez of the DEA’s Cannabis Investigations Section said his agency worked closely with the Environmental Protection Agency in preparing its proposal. “We will abide by all the conditions on the label,” Ramirez said.

Kills Much Faster

Paraquat’s virtues as a marijuana killer have produced high enthusiasm for the herbicide at the drug agency. The poison can kill marijuana within hours and is much faster-acting than the other two herbicides being considered.

The speedy qualities of paraquat would allow the agency to conduct eradication operations in an efficient manner, the agency argues. With a slower-acting herbicide, drug agents would have to stand guard over a marijuana patch for many hours or days while the plants wilt. Such guarding is expensive to the agency and dangerous to the guards, who are vulnerable to attack from the growers.

Nonetheless, agency officials are obviously aware of the sensitivity of the paraquat issue. When told that some state officials expressed surprise that they had not been notified of the DEA’s plans, Ramirez said: “They are surprised because of the questions you (the reporter) are asking. You are assuming the DEA is going to spray and the DEA is not assuming anything.”

List of Recipients

Ramirez referred a reporter to an extensive list of recipients contained in an appendix to the environmental assessment. That list--mainly law enforcement agencies--did not contain the names of agencies in California responsible for pesticide regulation. Some agencies that were listed in the appendix said they had no record of receiving copies of the document.

No matter which eradication method is chosen, the environmental review makes it clear that the marijuana-killing program is a large-scale effort. It estimates the value of the domestic marijuana crop at more than $1 billion a year and says eradication efforts would be conducted on about 15,000 acres of non-federal land nationwide. Last year, the document says, drug officers found 21,000 plots of illegal marijuana in this country.

Under the preferred approach, drug officers would have available to them all three herbicides plus mechanical methods for destroying plots. If paraquat were chosen for all eradication efforts--an unlikely prospect--the program would consume about 385 tons of the herbicide, or about 11% of the total used in this country each year, the document says.

California Targeted

The environmental review also suggests that California would be the main target of the program. Last year this state received the largest share by far of DEA funds for mechanical eradication. In this state, 2,002 plots were wiped out, at a cost of $1.1 million. The next largest state, Hawaii, received $186,000.

The DEA argues that the risks from paraquat use would be minimal. After application, paraquat that reaches the soil would quickly bind to clay particles and be rendered harmless, the document says. The only risky exposures to humans would occur if people consumed large amounts of unwashed berries or lettuce that had been covered by drifting chemicals, or if they ate rabbits or deer that had been sprayed directly with any of the three herbicides.

“The probability of this actually occurring is considered to be extremely low,” the environmental assessment say.

However, some environmentalists have questioned those conclusions. Speaking at the Los Angeles hearing, Elizabeth Reifsnider of the Sierra Club contended that the DEA failed to consider much of the scientific evidence on paraquat. Those studies document serious health threats to people applying paraquat and to wildlife foraging on treated vegetation.

Geese Get Dose

Referring to one wildlife incident in 1973, Reifsnider said 61 out of a flock of 84 geese were killed when heavy rains washed paraquat-contaminated water into their feeding area. Other incidents have shown that paraquat sprayed from airplanes can drift for several miles from the intended target, she contended.

Other environmentalists predict that the legality of paraquat’s use for marijuana control ultimately will be decided in the courts, much as it was in the case of the 1982 lawsuit involving spraying on federal lands.

Thus far, the issue appears to pit California against the federal drug agency and the Environmental Protection Agency.

California officials say they regard the use of paraquat for marijuana eradication to be illegal. Their opinion stems from their interpretation of the paraquat label, which describes in detail the permitted uses for the pesticide. Pesticide labels are written by the Environmental Protection Agency and each use is included on the label only after research has shown that use to be safe.

“If the use isn’t there, it isn’t allowed,” said Van Cheney, supervisor for pesticide regulation at the Food and Agriculture Department. “The paraquat label has a specific list of all plants that are approved for treatment, and marijuana is not one of them.”

Interpretation Matter

In Washington, the EPA says the California interpretation of the paraquat label is incorrect. Paraquat can be used legally for marijuana control, the agency says, on the basis of the drug’s classification as a “broad-leaf weed.”

“Paraquat is registered for broad-leaf weed control in what is known as ‘non-crop’ areas,” said Carole Gray, program specialist at the EPA’s Office of Pesticide Programs. “In our judgment a forest clearing would be included in non-crop areas and paraquat’s use in such a location would be consistent with the label.”

After hearing the EPA’s opinion of the label issue, California’s Peterson chuckled. “That is certainly a liberal interpretation,” he said. “We would want to talk to the EPA about that in great detail.”

California officials said they probably would not defy the EPA if a paraquat project was proposed in this state, but they did not rule out the possibility of a lawsuit. They said it is more likely that they would exercise the state’s authority to place conditions over any permits for the use of the pesticide. They declined to speculate on the nature of the conditions.

In San Francisco, one of the attorneys who filed the 1982 lawsuit said many of the same legal arguments could be applied to paraquat use on non-federal lands. “One of our contentions was that paraquat had not been registered for use in marijuana control. I don’t see why the same reasoning wouldn’t apply in this case,” said Buck Parker of the Sierra Club Legal Defense Fund. “If you ask me, I’d say there’s going to be a another lawsuit.”