Hergenreder family
Now playing
06:47
Researchers looking for cause of vaping-related illnesses
Fox News/Twitter
Now playing
01:33
ADL wants Fox News to fire Tucker Carlson over racist comments
CNN
Now playing
02:36
The truth behind Covid-19 vaccines for sale on the dark web
Now playing
04:22
Levi's CEO has message for Mitch McConnell
Now playing
01:54
'You think I'm racist': Former Fox News host storms off camera
Korie Robertson and Willie Robertson of the reality series "Duck Dynasty" attend the Capitol File 58th Presidential Inauguration Reception at Fiola Mare on January 19, 2017 in Washington, DC.
Paul Morigi/Getty Images
Korie Robertson and Willie Robertson of the reality series "Duck Dynasty" attend the Capitol File 58th Presidential Inauguration Reception at Fiola Mare on January 19, 2017 in Washington, DC.
Now playing
01:46
'Duck Dynasty' stars discuss raising biracial son on new show
FOX/"The Masked Singer"
Now playing
01:24
Nick Cannon makes big splash in 'Masked Singer' return
The Drew Barrymore Show/YouTube
Now playing
01:26
'Mom' star speaks out about not having kids in real life
Heinz ketchup packets are shown in New York on Monday, August 22, 2005. H.J. Heinz Co., the world's biggest ketchup maker, said first-quarter profit fell 19 percent on expenses to cut jobs and sell businesses.  (Photo by Andrew Harrer/Bloomberg via Getty Images)
Andrew Harrer/Bloomberg/Getty Images
Heinz ketchup packets are shown in New York on Monday, August 22, 2005. H.J. Heinz Co., the world's biggest ketchup maker, said first-quarter profit fell 19 percent on expenses to cut jobs and sell businesses. (Photo by Andrew Harrer/Bloomberg via Getty Images)
Now playing
01:53
Restaurants face a nationwide ketchup packet shortage
Camerota Berman both
CNN
Camerota Berman both
Now playing
02:33
CNN anchor Alisyn Camerota gets surprise tribute from co-anchor
Citigroup Chairman Richard Parsons delivers remarks on the US economy at the New York State Bar Association meetings in New York, January 28, 2009. Troubled US banking giant Citigroup last week named Parsons as its new chairman, the longtime top executive at media giant Time Warner, to steer it through its most challenging period.  AFP PHOTO / Emmanuel Dunand (Photo credit should read EMMANUEL DUNAND/AFP via Getty Images)
EMMANUEL DUNAND/AFP/AFP via Getty Images
Citigroup Chairman Richard Parsons delivers remarks on the US economy at the New York State Bar Association meetings in New York, January 28, 2009. Troubled US banking giant Citigroup last week named Parsons as its new chairman, the longtime top executive at media giant Time Warner, to steer it through its most challenging period. AFP PHOTO / Emmanuel Dunand (Photo credit should read EMMANUEL DUNAND/AFP via Getty Images)
Now playing
02:47
Dick Parsons: Georgia law is a bald-faced attempt to suppress Black vote
Courtesy of Warner Bros. Picture
Now playing
02:54
'Godzilla vs. Kong' is a pandemic box office hit
Now playing
01:30
5 ways to cut your plastic waste
CNN/Getty Images
Now playing
04:40
Stelter: After elevating Gaetz, Fox News barely covering scandal
NASA/Goddard/University of Arizona
Now playing
01:08
See NASA spacecraft successfully land on an asteroid
Now playing
06:51
Alisyn Camerota's kids wish her good luck in new role on CNN
(CNN) —  

Vitamin E acetate, an additive sometimes used in THC and other vaping products, may be to blame for a national outbreak of e-cigarette-related lung injuries that’s linked to dozens of deaths, according to US Centers for Disease Control and Prevention officials.

Dr. Anne Schuchat, the principal deputy director of the CDC, said she would characterize it as a breakthrough in the agency’s investigation, although more tests are necessary.

“These new findings are significant,” Schuchat said during a press briefing on Friday. “We have a strong culprit.”

There is still more work to do and the CDC said it is continuing to test for a wide range of chemicals.

“This does not rule out other possible ingredients,” Schuchat said. “There may be more than one cause.”

The CDC says its tests found vitamin E acetate in samples taken from 29 patients who were sick with vaping-related illness in 10 states. THC, or tetrahydrocannabinol, the primary psychoactive component of the cannabis plant, or its metabolites were detected in 23 of 28 patients. Nicotine metabolites were detected in 16 of 26 patient specimens.

During the press briefing, CDC’s Dr. James Pirkle described vitamin E acetate as “enormously sticky” when it goes into the lungs, and it “does hang around.” Pirkle said it wouldn’t be unusual for THC to be absent from some of the samples because it leaves the lungs faster. He added finding THC in 82% of the samples from 28 patients was “noteworthy.”

In September, New York health officials linked cases of severe lung illness to vitamin E acetate in cannabis-containing vaping products. At the time, investigators said it was “a key focus” of the state’s investigation into the illnesses.

“The CDC’s reporting supports what New York State’s Wadsworth Center Lab has found in vape products tested since early September and reinforces the importance of the role that Vitamin E acetate may play in the current outbreak of vaping related illnesses,” New York Gov. Andrew Cuomo said in a statement on Friday. “While no definitive cause has been found, as I’ve said from the very beginning: if you don’t know what you are smoking, don’t smoke it.”

Until the investigation is complete, the CDC suggests people refrain from using all vaping products with THC, no matter where people buy them. The investigation has found that many of these products patients used were bought online or received through friends or family, rather than through vaping shops or at licensed THC dispensaries.

Vitamin E is used in several products, such as lotions and in supplements, but the CDC said there is a “big difference” in putting vitamin E on the skin or swallowing it in pill and in inhaling the oily vitamin.

Get CNN Health's weekly newsletter

Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team.

Dr. Jennifer Layden, the chief medical officer and state epidemiologist with the Illinois Department of Public Health, said in the press briefing that in her state, they found the majority of cases of the people who were sick used THC, and that their materials came from “informal sources.” In Illinois, she said, they had not had any cases associated with the state’s medical marijuana program.

So far, there have been 2,051 cases of vaping associated illnesses, reported in every state, except for Alaska, as of November 5. States have reported at least 40 deaths.

Clarification: This story and headline has been updated to reflect that vitamin E acetate, which is sometimes used a thickening agent in THC vaping products, has been linked to vaping-related lung injuries.