Fabian Castillo suffered from crippling anxiety when his uncle presented him with a marijuana pen one day last December.
"This will help you calm down," Castillo said, his uncle tells him.
Over the next few months, the vape worked as advertised. Castillo, who has just graduated from high school in Southern California, has proven to be softer and more productive.
At the time, he had no idea that he was using what he now believes to be a bot-vap pen filled with a toxic mix
But on August 2, Castillo's breathing intensified. His mother took him to the emergency room, where, according to her, the x-ray showed severe damage to his lungs.
"I couldn't breathe, I couldn't talk. "Castillo, 1
He spent the next nine days in a medically induced coma. Eight weeks later he was still struggling to breathe deeply.
The growing popularity of vaping products – both legal and knocking in 46 states, according to federal health officials.  "We're dealing with this epidemic, "says Dr. Melody Pirzada, a pediatric pulmonologist at NYU Winthrop Hospital in Long Island, New York.
The Centers for Disease Control and Prevention says that most patients have reported using a vaccine containing THC, psychoactive ingredient in marijuana Some state health officials have indicated that vitamin E acetate, a solvent used to "cut" cannabis for use in bath pens, may be responsible for the epidemic.
But no substance or product has yet been linked to all cases of vaping-related pulmonary disease, the CDC says, leaving the medical community to fight an outbreak of a health crisis for some unknown reason.
At the same time, the FDA is fighting the police over what has quickly grown into a billion-dollar industry. with a thriving black market, experts say
The result: Americans have access to an astonishing assortment of THC vape pens without having a grasp on what they actually have.
Seeking answers, NBC News commissioned one of the nation's leading cannabis testing facilities to test samples from THC cartridges – a total of 18 – obtained from legal dispensaries and unlicensed dealers.
The results are deeply disturbing.
Of the three purchased from a legal dispensary in California, the CannaSafe testing company does not detect heavy metals, pesticides or residual solvents such as Vitamin E.
But 13 of the remaining 15 samples of black market THC cartridges contain Vitamin E.
] CannaSafe also tested 10 of the unregulated pesticide cartridges. All 10 tested positive.
All products contain myclobutanil, a fungicide that can be transformed into hydrogen cyanide on combustion.
"You certainly don't want to smoke cyanide," says Antonio Frasier, vice president of operations at CannaSafe. "I don't think anyone would buy a cart that was labeled with hydrogen cyanide."
Pierzada described the existence of microbutanil as "very disturbing." "It will cause a very toxic effect on the lungs," she said.
The New York Pulmonologist also expressed concern about the presence of vitamin E, which is also known to cause significant lung damage when inhaled in THC mixtures. , "It should not be inhaled into your lungs," she said.
Pierzada treated four patients, all teens suffering from lung damage. She said testing on the same vaping mix used by one of her patients revealed the presence of Vitamin E.
An 18-year-old boy arrived at the hospital with pneumonia-like symptoms. But within 48 hours, Pirzada says, his condition deteriorates rapidly and he is put on a ventilator.
He spends five days in support of life before he can breathe on his own and recover with the help of steroids. "He needed very high levels of support to keep him alive," Pirzada says.
Such patients are hospitalized throughout the country. In the summer, an 18-year-old girl arrived at UCLA Health with bad coughing, fever, nausea and shortness of breath. Within 48 hours, the lung function deteriorates to the extent that doctors send it to the Institute for Intensive Care and attach it to a respirator.
The teenager who reports that he has been drinking tobacco and pot products every day for the past two years has eventually improved.
"She got sick very, very quickly," says Dr. Catherine Melamed, a pulmonologist , saved the life of a teenage girl.
Less than 15 miles from UCLA Health sits a 12-block downtown Los Angeles area full of vape shops. The stores sell empty cartridges and packaging, making it easy for anyone with access to THC and a solvent such as Vitamin E to make their own bouquet vape products.
California Legalizes Marijuana for Recreation for Adults Over 21 in 2016.  David Downs, head of the California Bureau of Leafly, an online publication dedicated to the cannabis industry, said downtown Los Angeles is acting as a deadline a supply chain destination originating in China.
"It all starts in China, where you can pick up empty cartridges for both the THC market and the nicotine market, as well as the additives, flavors and thickeners that are put into these cartridges, along with THC oil," said Downs.
"This is a very deep, mature and advanced industry that starts in China and ends in our own backyard."
Downs says that anyone who buys a zippered zipper puts himself at risk.
"I said, 'Look, if you buy a fake Geese bag, it won't hurt your lungs, but if you buy a fake vape cartridge, it just might. "Downs said.
Acting FDA Commissioner Ned Sharpless, speaking to a congressional committee Wednesday, said investigators are working to identify dangerous products and "follow the supply chain."
"The FDA is not pursuing any personal action use of any vaping products, our interest is in suppliers, "Sharpless told the House Energy and Commerce Subcommittee, which has an oversight body over the FDA.
"But to be clear, if we determine that someone produces or distributes illegal, counterfeit vaping products that cause illness and death for personal gain, we would consider this a criminal act."
The American Vapping Association insists, that the epidemic is related to THC oils and cuts.
One of the stores visited by NBC News in Los Angeles sells packaging for Dank Vapes Gorilla Glue, the same vape th brand in Castillo used before landing at the hospital. The product is in no way affiliated with Gorilla Glue, the company that produces super glue and other adhesives.
An aspiring singer, Castillo has not yet returned to full health. Every time he tries to take a deep breath, he feels like he's just running down the stairs. Castillo also copes with a strange sensation that leaves him feeling that he is falling and causing his body to tremble.
He said he spoke to stop others from putting their lives at risk using vapes.
"Everything was paused because I decided to get drunk," Castillo said. "I thought it was safe."