SAN FRANCISCO (KGO) -- Thousands of lung injury cases and dozens of deaths have been associated with vaping, including four right here in California, with one in Marin County.
Vaping is the heating up of cannabis or nicotine extracted from tobacco, creating a water vapor that you can inhale.
ABC7 News Investigative Reporter Melanie Woodrow has been digging into why people are getting sick now.
Vaping has been around for a number of years, but investigators say something changed this summer, making people sick. Despite the CDC's recommendation that people stop vaping, a lot of people are still doing it.
Stephen Shub calls himself a deadhead -- in the late 60s, Shub discovered pot.
"I was a regular consumer of whatever it was we used to smoke back then," said Shub.
Shub later switched to vaping.
"Vaping is a 21st century phenomenon," said David Downs, Leafly Editor.
Downs has been on the cannabis beat nine years.
"Vaping took over because people wanted to make healthier choices about consuming cannabis and not smoking," said Downs.
But that choice now appears to be producing dire consequences for some vapers.
According to the Centers for Disease Control and Prevention, as of Nov. 13, there have been more than 2,000 e-cigarette or vaping product use associated lung injury cases.
There have been 42 people who have died, including four right here in California -- one in Marin County.
"We saw a perfect storm this summer," said Downs.
Downs believes that perfect storm was a combination of a decrease in the price point for cannabis due to legalization and a decrease in the cannabis supply on the black market, encouraging non-licensed manufacturers of cannabis oil to dilute their product more and more, thereby stretching their profits.
He says consumers caught on and started performing what Downs calls the bubble test, associating the thickness or viscosity of THC oil with purity. If the bubble in the vape cartridge didn't move, consumers would think their product hasn't been diluted.
"Black market cutters and chemists responded by coming up with an additive that can cut THC oil while still keeping it thick," said Downs.
Vitamin E Acetate is one of those additives. The CDC collected lung fluid samples from 29 victims. They found Vitamin E Acetate in all 29 samples and THC in 23 of the samples.
The CDC says the findings do not rule out other possible compounds that may be causing lung injuries but help investigators better understand the potential ingredients that may be contributing to the cause.
According to the CDC, no one compound or ingredient has emerged as the cause of illnesses to date, a point echoed by the California Department of Public Health.
"The challenge with the multiple patterns of lung injury emerging is that it suggests there are likely multiple mechanisms of injury and/or multiple different chemicals that could be the culprit," said Charity Dean, California Department of Public Health Assistant Director and State Public Health Officer.
Anresco Laboratories in San Francisco is one of the state's licensed cannabis testing laboratories.
Employees here homogenize cannabis samples, making sure they're even, random and representative, then test the samples according to state regulations. Here's what they're looking for:
"Potency, pesticides, microbial contaminants, heavy metals," said Josh Richard, Director of Cannabis Services at Anresco Laboratories.
If a cannabis product doesn't pass a test, the state requires that it's reprocessed or destroyed.
Anresco laboratories recently analyzed illicit versus regulated cannabis oils for pesticides and Vitamin E Acetate even though California does not require Vitamin E Acetate testing.
Of more than 200 cartridges from licensed manufacturers tested, none had significant concentrations of Vitamin E Acetate.
Of 11 illicit market cartridges tested, five had Vitamin E Acetate concentrations of 34 to 48 percent.
All 11 illicit market cartridges failed California's pesticide residue tests.
"We were baffled... like how could this be happening," said Anresco employee Cathy Cheng.
UCSF Medical Toxicologist Dr. Neal Benowitz has been studying what happens when Vitamin E Acetate is heated at different levels to see whether it's broken down to something that's toxic.
His feelings about Vitamin E Acetate and other thickening oils:
"They're healthy if you eat them, they're healthy if you put them on your skin, but they're not healthy if you heat them up and inhale them," said Dr. Benowitz.
"When it's inhaled, basically it forms a thick cloud of oily substance goes into your lungs and gets absorbed slowly, so basically it can coat your lungs with an oil," he continued.
According to the CDC, two findings stand out linked to the e-cigarette or vaping product use associated lung injury cases. THC is present in most of the samples tested by the FDA to date, with most patients reporting a history of using THC containing products.
The latest national and state findings suggest products containing THC obtained off the street or from other informal sources are linked to most of the cases and play a major role in the outbreak.
Anresco Laboratories' director of cannabis services says there are ways to know if you've purchased an illicit product online.
Beware of any sort of marketing to children or suspicious use trademarked property like a Flintstones logo.
Also, watch out for claims the product is "organic" on the packaging.
Some illicit packaging looks especially convincing because it's a fake of a real licensed brand, complete with the California sticker, potency label and even batch number.
"You can pretty much buy any packaging, any labels and branding from any of the major vape cart manufacturers online right now, have it shipped to your house and fill it with whatever oil you like, which is pretty scary," said Richard.
That's why some licensed manufacturers like Rove are now putting QR codes on their products. Users can scan the code with their cellphone to verify they have an authentic product from a licensed retailer.
Despite e-cigarette and vaping product use associated lung injuries and deaths, along with the unknown of what specifically is causing both, Stephen Shub says he'll continue vaping daily.
"Take a hit or two, turn on the music," said Shub.
Shub says he will only buy regulated products from licensed retailers.
The CDC recommends that you do not use e-cigarette or vaping products that contain THC, particularly those purchased off the street.
For a look at more stories and videos by Dan Noyes and the ABC7 News I-Team.