Legalization of marijuana at the state level has resulted in at least 10 recorded instances of fires or explosions at facilities that extract hash oil.

States are facing a new danger as legal marijuana spreads across the country: Explosions and fires at cannabis factories are sending workers to the hospital with severe burns, revealing the nascent industry's lack of proper safety standards.

In the 33 states where the drug is legal for medical or recreational use, at least 10 fires or explosions have occurred in the past five years at facilities that extract hash oil used in edible products. Nearly all resulted in serious injuries for production-line staff.

“The extraction process is continuing to evolve," Raymond Bizal, director of California and Oregon regional operations for the National Fire Protection Association, told POLITICO. "The fire-safety industry has to play catch-up.”

Most of the states where marijuana is legal offer no safety and health guidance for the new industry. The National Institute for Occupational Safety and Health, which researches work-related injury and illness, has conducted only two hazard evaluations of legal marijuana facilities, neither of which focused on the extraction of hash oil. Even in those states that do offer safety and health guidance — Colorado, California, Michigan, Oregon, and Washington — fire safety officials complain that worker safety protections are often inadequate.

Marijuana legalization is fast becoming a mainstream position for Democratic presidential candidates. Sen. Kamala Harris (D-Calif.) called for federal legalization on Feb. 11, and even confessed that "a long time ago" she'd smoked the stuff herself. "I did inhale," she said (an allusion to candidate Bill Clinton's much-mocked claim in 1992 that he did not). Sen. Cory Booker (D-N.J.), another presidential hopeful, introduced a bill in 2017 to legalize marijuana at the federal level.

But labor unions complain that state governments are moving too swiftly to license producers, outpacing the states' ability to inspect production facilities for potential safety violations. Unions also want more certification training to teach workers how to handle machinery and equipment properly.

Extracting hash oil from cannabis is dangerous because typically it requires pouring highly-flammable butane or some other volatile solvent into a cannabis-filled pipe. The butane strips THC, the active ingredient in marijuana, from the cannabis plant, which then drips down in liquid form and is collected for consumption in cannabis-laced chocolate, butter, or tea, or, more directly, in hash-oil vape pens.

In Arizona last year, a fire at a legal medical marijuana facility erupted after a worker improperly stored a can of butane, causing an explosion.

"This is something fire departments and law enforcement and city code officials will have to deal with," Fire Capt. Mark Dillon of Coolidge, Ariz., told ABC’s Nick Ciletti at the time.

When performed in illegal marijuana operations — often located in residential locations — the processing of marijuana for hash oil has long been known to cause frequent deadly explosions. In 2017 the Drug Enforcement Agency recorded fires or explosions in roughly 10 percent of all illegal extraction labs nationwide.

With hash oil extraction now legal in 33 states, what once was a hazard for law enforcement to address is fast becoming the responsibility of state regulators of occupational health and safety.

Two of the 33 states bar the use of butane to extract hash oil in professional operations. New York, for instance, allows extraction only when the agent used is carbon dioxide or alcohol; a processor who wishes to use an alternative method must receive specific approval. Eleven states require a “closed loop” system that contains the flammable agent, preventing its release into the air, where it can ignite. Rhode Island, which is weighing whether to legalize marijuana, would bar use (and therefore extraction) of hash oil except in certain medical situations.

Following an uptick in explosions in Colorado, fire officials there persuaded the National Fire Protection Association, which establishes a fire code for the whole country, to amend its rules to address hazards at facilities that grow and extract marijuana. The revised code requires any hazardous hash-oil extraction process to be performed in a non-combustible room, in a building that contains no child or health care facilities. Staff must be trained on safe operation of the extraction equipment, and the extraction room must be equipped with a gas detection system and multiple fire extinguishing systems.

In states that are weighing legalizing marijuana, labor groups are pressing to include in legalization bills “labor peace provisions” that require marijuana processors to ease the path to unionization. Doing so, they say, keeps “an open line of communication” on worker safety matters. “We see unions in our work as providing a safeguard for the workers,” said Nikki Kateman, communications director for the United Food and Commercial Workers' Local 338, which is advising New York on safety matters as it legalizes adult marijuana use this year.

Safety at legal marijuana facilities remains mostly a state matter because the federal government hasn’t legalized consumption.

Federal safety and health standards do apply to marijuana companies, but many are too small to fall under the jurisdiction of the Occupational Safety and Health Administration. Since 1977, a rider that's included routinely in appropriations bills prevents the agency from inspecting farm operations with 10 employees or fewer.

Vermont, which has its own occupational safety and health program, says Vermont OSHA has “not performed any inspections or investigations associated with marijuana cultivation or manufacturing.” The first medical dispensary opened in the state in 2013.

Hash-oil processing “can be done safely,” said Bizal, of the National Fire Protection Association, when it is “done properly and following the rule and regulations.” But as the industry has grown, safety hazards have proliferated in legal marijuana operations — some drawing steep fines and even felony convictions of legal proprietors.

In December, California’s occupational safety and health agency fined a cannabis manufacturer $50,470 after an explosion badly burned a worker who was using propane to extract oil. In June, an explosion at a cannabis producer in Washington sent one worker to the hospital, although it was unclear whether the blast was attributable to hash-oil extraction.

In 2016, two workers were sent to a burn unit after an explosion at a medical marijuana processor in Oregon. Felony charges were later brought against the business owner. "This is really not a drug case; this is a case about recklessness and an industrial accident," then Oregon's Clatsop County District Attorney Josh Marquis told the Oregonian at the time.

That same year in New Mexico, the federal Occupational Safety and Health Administration fined a medical marijuana dispensary $13,500 after a hash-oil explosion so powerful that it separated the roof from the wall and sent two employees to the hospital. One 29-year-old worker “suffered third-degree burns to a high percentage of his body, had a prolonged stay in the intensive care unit and needed multiple skin grafts,” according to the Santa Fe New Mexican.

The United Food and Commercial Workers has organized thousands of cannabis workers across the country, often using safety issues as a prod. In New York, where Local 338 is advising the state on health and safety inspection procedures, the union's secretary-treasurer, Joe Fontano, says “having a collective bargaining agreement allows the union to ensure that proper safety procedures are in place.”

UFCW fears that if states move too quickly on legalization, that will compromise their ability to monitor marijuana workers' health and safety. “If you over-license," one UFCW official said, "you ... put too much of a burden on inspectors and the enforcement division.”

Worker safety is a matter of growing urgency because legal marijuana is a booming business. In 2018 there were an estimated $10.4 billion in U.S. sales of legal medical and recreational marijuana. That translated into 259,000 jobs, according to cannabis research firm New Frontier Data. Some estimates project sales to reach $40 billion by 2021.

If states move too slowly to legalize, however, they risk ending up with more illegal hash-oil extraction operations. Because these aren't supervised at all, they're much more dangerous. In 2017 the DEA’s El Paso office identified 260 illegal extraction labs across the country, about one-third in residential locations. Fires or explosions were reported in more than 10 percent of them.

At this point marijuana is likelier to be at least partly legal in any given state than not. Thirty-three states, the District of Columbia, Guam and Puerto Rico have legalized marijuana, most for medical use, and 10 states and the District of Columbia permit recreational use as well, according to the National Conference of State Legislatures. Another 13 states allow the use of CBD products (the non-intoxicating oil in the plant, usually used to treat pain and anxiety) for medical reasons in limited situations. That leaves only four states — Idaho, South Dakota, Nebraska and Kansas — with no laws permitting marijuana use under any circumstances.

Two jurisdictions, Vermont, and Washington D.C., legalized marijuana use but barred retail sale of the product. These jurisdictions maintain oversight over medical marijuana dispensaries and allow recreational use only if users purchase it elsewhere, receive it as a gift, or grow it themselves. That may encourage residents to obtain concentrated hash oil products illegally, or to extract them at home.

“It’s a big problem that states face after possession becomes legal, but before retail sales and businesses are legal,” Morgan Fox, media relations director at the National Cannabis Industry Association, explained to POLITICO. “There’s no source for these extracted products and concentrates other than the illicit market.”

Some states see a possible solution to hash extraction's workplace dangers in not allowing extraction at all. In addition to Rhode Island's pending legislation to legalize marijuana but not hash oil, the Arizona Supreme Court is considering whether marijuana extracts are legal under the state's medical marijuana law.

But management-side attorneys warn that increased regulation will likely make it more difficult for cannabis employers to find trained staff, who must pass certain background checks and receive approval by state’s marijuana regulatory bodies.

“Contracting out work isn’t really an option in this industry,” explained George Voegele, a member of Cozen O'Connor's Labor & Employment practice. “It’s difficult for employers to make significant changes to their employee rosters.”