Maddie Nelson, 18, had vaped a variety of products for three years. Then, this summer, she began experiencing chest pain, nausea, and a fever. She checked into a hospital near Salt Lake City, Utah, but her symptoms worsened, and she had to be hooked up to a machine to help her breathe. Doctors placed her in a medically induced coma for three days, while they frantically worked to save her life.

Nelson is among a growing number of people who’ve wound up in emergency rooms with lung injuries tied to vaping. As of mid-October, nearly 1,500 people had suffered from severe vaping-related illnesses and 33 had died, according to the Centers for Disease Control and Prevention (C.D.C.).

Maddie Nelson, 18, had vaped a variety of products for three years. Then, this summer, she began experiencing chest pain, nausea, and a fever. She checked into a hospital near Salt Lake City, Utah, but her symptoms worsened. She eventually had to be hooked up to a machine to help her breathe. Doctors were forced to place her in a medically induced coma for three days. They then frantically worked to save her life.

Nelson is among a growing number of people who’ve wound up in emergency rooms with lung injuries tied to vaping. As of mid-October, nearly 1,500 people had suffered from severe vaping-related illnesses, and 33 had died, according to the Centers for Disease Control and Prevention (C.D.C.).

Federal health officials are still trying to determine which products and substances are causing the illnesses. But as their investigation continues, they’ve issued a stark warning to stop using vaping products immediately, particularly those containing THC, the chemical in marijuana that makes users high. Spurred by the illnesses and by the explosive growth of vaping among teens, many states are cracking down on flavored e-cigarette sales, and the Trump administration has said that it would draft a ban on them too.

“These are really serious injuries in the lung,” says Dr. Anne Schuchat of the C.D.C., “and we don’t know how well people will recover from them, whether lung damage may be permanent.”

Federal health officials are still trying to determine what’s happening. They’re looking into which products and substances are causing the illnesses. But as their investigation continues, they’ve issued a stark warning to stop using vaping products immediately. And they’ve warned people to be even more cautious about products that have THC in them. That’s the chemical in marijuana that makes users high. The illnesses and the explosive growth of vaping among teens have moved states to act. Many of them are cracking down on flavored e-cigarette sales. The Trump administration has said that it would draft a ban on them too.

“These are really serious injuries in the lung,” says Dr. Anne Schuchat of the C.D.C., “and we don’t know how well people will recover from them, whether lung damage may be permanent.”

Like Nelson, many of those affected have been young people—about 36 percent of patients were 20 years old or younger. Vaping among American teens has skyrocketed in recent years. More than a quarter of high school students say they’ve vaped nicotine in the past month—up from about 12 percent in 2017, according to the C.D.C. (see graph).

Teens have especially been attracted to the sleek devices and the flavors made by Juul Labs, which now dominates the market. That may not be accidental. Last year, the Food and Drug Administration began investigating whether Juul Labs intentionally marketed to youth. The company denies that it sought to hook teens and insists its products are for people who want to quit smoking traditional cigarettes.

Invented more than 15 years ago, e-cigarettes were intended to be a healthier alternative to tobacco. But many doctors have long cautioned that nicotine, the highly addictive substance that’s in both traditional cigarettes and e-cigarettes, is especially harmful to teenagers’ developing brains. Plus, they say, we don’t really know how safe e-cigarettes are because they haven’t been around long enough to study all their effects.

Like Nelson, many of those affected have been young people. In fact, about 36 percent of patients were 20 years old or younger. Vaping among American teens has skyrocketed in recent years. More than a quarter of high school students say they’ve vaped nicotine in the past month. That’s up from about 12 percent in 2017, according to the C.D.C. (see graph).

Teens have especially been attracted to the sleek devices and the flavors made by Juul Labs. The company now dominates the market. It may not be accidental that its products appeal to younger audiences. Last year, the Food and Drug Administration began investigating whether Juul Labs intentionally marketed to youth. The company denies that it sought to hook teens. It insists its products are for people who want to quit smoking traditional cigarettes.

E-cigarettes were invented more than 15 years ago. They were intended to be a healthier alternative to tobacco. But nicotine, a highly addictive substance, is in both traditional cigarettes and e-cigarettes. Many doctors have long cautioned that nicotine is especially harmful to teenagers’ developing brains. Plus, they say, we don’t really know how safe e-cigarettes are because they haven’t been around long enough to study all their effects.

“The truth of the matter is, we have so little experience with vaping, relative to the experience we have with cigarettes,” says Dr. Emily Chapman, chief medical officer for the Children’s Minnesota hospital system. “Recall how long it took us to figure out that cigarettes were linked to lung cancer. There is so much we don’t know.”

Now the surge in vaping-related illnesses is exactly what many doctors feared would happen. Patients typically show up in emergency rooms with pneumonia- and flu-like symptoms and shortness of breath. Many need to be hooked up to machines that pump oxygen directly into the bloodstream. A study of lung tissue samples from 17 patients found that the injuries can look like what you’d expect to see in someone exposed to a toxic chemical spill.

Health investigators appear to be getting closer to identifying at least one of the culprits: vaping products containing THC. Of the hundreds of patients with information on substances used, about 78 percent reported vaping THC, with or without nicotine. However, 10 percent reported vaping only nicotine.

Many patients said they’d purchased their vaping products illegally—either on the streets, through friends and family, or online. Health officials are especially concerned about illegal vaping products, because they’re untested and often diluted with cheap substances that are toxic to inhale.

“The truth of the matter is, we have so little experience with vaping, relative to the experience we have with cigarettes,” says Dr. Emily Chapman, chief medical officer for the Children’s Minnesota hospital system. “Recall how long it took us to figure out that cigarettes were linked to lung cancer. There is so much we don’t know.”

Now the surge in vaping-related illnesses is exactly what many doctors feared would happen. Patients typically show up in emergency rooms with pneumonia- and flu-like symptoms and shortness of breath. Many need to be hooked up to machines that pump oxygen directly into the bloodstream. A study of lung tissue samples from 17 patients found that the injuries can look like what you’d expect to see in someone exposed to a toxic chemical spill.

Health investigators appear to be getting closer to identifying at least one of the culprits: vaping products containing THC. Of the hundreds of patients with information on substances used, about 78 percent reported vaping THC, with or without nicotine. However, 10 percent reported vaping only nicotine.

Many patients said they’d purchased their vaping products illegally. They got them either on the streets, through friends and family, or online. Health officials are especially concerned about illegal vaping products. These types of products are untested and often diluted with cheap substances that are toxic to inhale.

Hoping to stop young people from getting hooked, a number of states, including Michigan, Rhode Island, and New York, have issued bans on flavored e-cigarettes. (The ban in New York was put on hold in early October while it was being fought in court.) Massachusetts has announced a four-month ban on all vaping products, and other states are considering bans too.

Facing mounting legal troubles, Juul Labs recently replaced its chief executive with a top official from Altria, a cigarette giant that owns a large share of Juul Labs. Some experts see the move as a sign that Juul is becoming more and more like Big Tobacco in its fight against stricter regulations.

As for Nelson, she began to recover, and was released from the hospital, but doctors don’t know whether her lung damage will be permanent. Since the incident, she and most of her friends have quit vaping, and she hopes more teens do too.

“I’d seen things of people getting sick before, and I would just scroll past it, and thought this can’t happen to me,” she told ABC4 News in Salt Lake City. “But it totally can, and it is not a fun thing to go through.”

Some states, including Michigan, Rhode Island, and New York, have issued bans on flavored e-cigarettes. They’re hoping to stop young people from getting hooked. The ban in New York was put on hold in early October while it was being fought in court. Massachusetts has announced a four-month ban on all vaping products. Other states are considering bans too.

Juul Labs is facing mounting legal troubles. It recently replaced its chief executive with a top official from Altria, a cigarette giant that owns a large share of Juul Labs. Some experts see the move as a sign that Juul is becoming more and more like Big Tobacco in its fight against stricter regulations.

As for Nelson, she began to recover, and was released from the hospital. Still, doctors don’t know whether her lung damage will be permanent. Since the incident, she and most of her friends have quit vaping, and she hopes more teens do too.

“I’d seen things of people getting sick before, and I would just scroll past it, and thought this can’t happen to me,” she told ABC4 News in Salt Lake City. “But it totally can, and it is not a fun thing to go through.”

With reporting by Sheila Kaplan of The Times.

With reporting by Sheila Kaplan of The Times.