(Bloomberg) -- Early this July, a previously healthy 21-year-old man came to the hospital with shortness of breath. His symptoms worsened so fast he had to be transferred by helicopter to the University of Utah Health in Salt Lake City. 

There, doctors were stumped. The man’s lungs were almost a complete white-out, as if he had pneumonia or a severe case of flu. But it was the middle of summer, far from flu season, and tests found no infection. The only thing out of the ordinary was that the patient had been vaping THC and nicotine products.

Doctors put the young man on a ventilator to help him breathe, then turned it to its maximum setting. He still wasn’t getting enough oxygen.

“I was scared to be honest,” said Sean Callahan, a University of Utah doctor who treated the patient. “This guy was very young, his parents were there, and I was worried he was going to die.”

Around the country, doctors have now seen hundreds of cases where patients — often youthful, previously healthy adults — have shown up in the emergency room, suddenly stricken with dangerous respiratory damage. Their lungs look like they’ve been ravaged by a disease, or as if they’ve been exposed to a noxious industrial chemical. But the thread that’s tied them together has been the use of vaping and e-cigarette devices, many with THC, the key psychoactive ingredient in cannabis. 

More than 450 cases of varying severity have been reported so far, according to the U.S. Centers for Disease Control and Prevention, along with multiple deaths. The illnesses have set off a sprint by public health officials, doctors and researchers around the country to try to identify the cause. 

The first Utah patient lived, after being hooked up to machines that added oxygen directly into his blood. But in the weeks after the man was treated, the hospital identified several more cases. By late July, doctors at the medical center were writing up an unusual finding in the patients’ lungs: Immune cells called macrophages were filled with oil, possibly because they had engulfed some of the ingredients from the vaping devices.

It wasn’t just Utah. There was a cluster of patients at Children's Hospital of Wisconsin. On July 25, the state’s Department of Health Services said it was investigating eight cases in adolescents who had been vaping.

The lung illness “gets worse really quickly,” said Jeffrey Kanne, a radiologist at the University of Wisconsin-Madison, which has had patients. On scans, “these are like what you see with acute lung injuries,” such as inhaling toxic substances in an industrial accident.

As word of the injuries began to spread this summer, doctors started to notice a pattern.

“We thought, ‘Wow, we are seeing the same things,’” said Scott Aberegg, a pulmonary and critical-care specialist at the University of Utah Health. For young patients, the mystery illness can be terrifying.

“They are having fevers, drenching night sweats, they feel like they can't breathe and their chest hurts,”  said Aberegg. “It is just a miserable, miserable condition to be in.”

The CDC said anyone who uses a vape device should consider stopping while public health officials investigate the cause. State health officials in New York have pointed to vitamin E acetate as a likely culprit. While thought to be harmless when used as a nutritional supplement, it could carry risks when inhaled and has been found in some products, said New York health officials. But the doctors interviewed by Bloomberg said the culprit is still unknown.

The CDC said on Friday that the lung-injury cases were appearing most often in people who used vaping products containing THC. While vaping pens with cannabis have boomed in states that have legalized the product, as well as on the black market, they come with unknown health effects. The recent spate of severe and sudden lung injuries have cast a shadow over the entire vaping category, both for cannabis and nicotine products.

The legal marijuana industry posted sales of more than $10 billion last year, but the federal prohibition on cannabis means there is scant research on the products. While some states, like California, have tightened quality and safety standards and now require tests for heavy metals, regulations vary from state-to-state. It’s up to consumers to rely on a fast-growing, fast-changing industry made up of big and small players. And the black market, of course, remains unregulated.

Hunting the Cause

Tracing the source of the vaping-related injury is particularly problematic. Unlike cigarettes, where a person might use one brand their whole life, people who vape tend to use a wide variety of substances and products, making it hard to narrow down which ingredients are the source of the problem.

When people are injured, the effects can be severe, and doctors are trying to quickly get the word out to colleagues who may be seeing the same things without knowing how to identify a cause. The New England Journal of Medicine on Friday published an analysis of 53 vaping lung-injury cases in Wisconsin and Illinois. According to the study, more than half of patients needed to be treated in the intensive-care unit, almost a third needed to be on ventilators, and one died.

Patients with lung injuries had used a variety of vaping products, with 80% using THC and 61% using nicotine, the researchers said. The most common THC product was sold under the Dank Vapes label, which was used by 24 of 41 patients who gave epidemiologists extensive interviews.

Dank Vapes' logo and packaging is used by several sellers, and it's difficult to trace back to any single maker of the products. Messages seeking comment from a company that markets products under the Dank Vapes brand name late Friday weren't immediately returned.

Marijuana vapes have gained popularity in recent years, with the disposable pens and cartridges valued by cannabis users concerned about the effects of smoking. So far, the reports of illnesses don’t appear to be dissuading consumers. Sales of legal marijuana vapes have “continued their steady growth and not shown signs of a slowdown,” according to Akerna Corp., a cannabis technology company that tracks the legal market.

Vaping has benefited from the perception that it’s healthier than smoking and the legal marijuana industry has positioned disposable pens as way to draw in new consumers beyond the stoners who still buy the majority of marijuana. Vapes are also at the center of a push to find a way to deliver consistent doses of weed, the way a glass of wine or shot is a standard measure of alcohol.

Legal brands often tout that their cartridges don’t use cutting agents like glycerine or Vitamin E acetate that make the contents less viscous and easier to heat and inhale, according to Aaron Riley, who runs CannaSafe, a Los Angeles-based cannabis testing lab that has grown since legalization in the state. But companies that are cutting corners, or targeting the black market, may use substances to dilute the oil with chemicals that can be dangerous when heated.

Zack Krubeck, 24, is the manager of Level Vape, a shop near Chicago's Wicker Park neighborhood. He says he thinks that some people try to “cheap out” when using THC products and then “get what they paid for.”

“It's cheaper, but not safe,” Krubeck said.

KushCo Holdings Inc., a cannabis vape and packaging company, makes about 66% of its revenue from the sale of vaping hardware, providing pens and empty cartridges to THC processors that fill them with oil and sell them at dispensaries. They also sell cutting agents used to dilute cannabis oil. In recent days, the company has fielded several calls from customers asking if they use vitamin E acetate in any of their cutting agents, said to Chief Executive Officer Nick Kovacevich. He says they don’t.

He’s doubtful that the recent headlines will curtail cannabis vaping, and argued it would push customers to seek out products from known brands sold in licensed stores.

“We’ve been conditioned that marijuana is safe, but this is a different ballgame,” he said. “This could be a catalyst that drives more people to the legal market.”

Vaping Users

While the injuries have made headlines, some consumers don’t seem particularly concerned — particularly compared to the well-known dangers of smoking, which is tied to hundreds of thousands of deaths every year in the U.S., many from long-time users who develop cancer after years of smoking.

In Dallas, a steady stream of customers came in and out of the All Vapes store on Friday afternoon. The store is on the main drag of a hip neighborhood known as Deep Ellum just outside downtown Dallas, populated by trendy restaurants, bars and funky storefronts. 

Brandalyn Bishop, 37, was a smoker for more than 20 years and used e-cigarettes to quit. She says she’s a little concerned about all the talk of safety issues, but trusts All Vapes’ products, which are made on-site. Anyway, “It’s not as bad as cigarettes,” she said.

Next to the cash register, store Manager Jessica Hash, 26, has set out a binder full of printouts responding to all the recent news about vaping making people sick. All Vapes says it uses only food-quality flavorings that are used in other consumer products such as ice cream and chewing gum. She thinks the problem is on the black market, with marijuana-infused cartridges using oil-based liquids and chemical-contaminated weed. 

“Vaping is a verb,” she says. “If people are saying vaping is making you sick, it’s like saying drinking is making you sick. Well, what are you drinking?”

Down the street at Wizard’s Vapor Bar & Smoke Shop, customer Kimberly Mathieu said she switched to vaping on her doctor’s advice to help her break a heavy cigarette habit. “It’s going to be bad one way or the other,” she shrugged.

There’s another option, said Aberegg, the lung specialist at the University of Utah: Follow the CDC’s advice, and don’t vape until the risks are better understood.

“It is completely not safe at all to vape THC-containing products. And it may not be safe to vape anything. We just don’t know yet,” Aberegg said.

--With assistance from Susan Warren, Anna Edney, Kristen V Brown and Kim Chipman.

To contact the editor responsible for this story: Drew Armstrong at darmstrong17@bloomberg.net, Timothy Annett

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