US health officials said Friday they had identified vitamin E acetate as the likely culprit behind a vaping-linked lung injury epidemic that has killed 39 people and sickened thousands.
Investigators have previously pointed to the oil, which is sometimes used as a thickening agent for vaping products that contain a psychoactive substance called THC, as a possible cause of the outbreak.
But they are more certain now after it was detected in all 29 patients selected for a lung fluid study carried out by the Centers for Disease Control and Prevention (CDC).
"These findings provide direct evidence of vitamin E acetate as the primary site of injury within the lungs," said Anne Schuchat, the CDC's principal deputy director, calling it a "very strong culprit of concern" and describing the new work as a breakthrough.
"No other potential toxins were detected in the testing conducted so far," she added.
Vitamin E acetate is found in many foods and is also used in cosmetics products like skin cream, but interferes with lung function when inhaled.
A CDC release added that more investigation was required to definitively confirm a causal link and that it remained possible more than one toxin was responsible for the current outbreak, which officials have called "e-cigarette or vaping product use associated lung injury" or "EVALI."
- Minimum age push -
The announcement came as President Donald Trump said he supported raising the minimum age for the purchase of e-cigarettes from 18 to 21 as part of a plan to curtail a surge in youth vaping.
But he also indicated that he was concerned about over-regulation of business, a sign the administration is considering stepping back from a previously announced ban on flavored e-juices popular among adolescents.
"We're going to be coming out with a very important position on vaping," Trump told reporters. "We have to take care of our kids, most importantly, so we're going to have an age limit of 21 or so."
He added that a policy paper would be issued next week.
The administration announced in September it would soon ban flavored products, but it appeared lobbying efforts by the vaping industry may have changed that position.
"We have a lot of people to look at, including jobs, frankly," said Trump. "It has become a big industry. We're going to take care of it."
The federal minimum age for purchasing tobacco products is 18, but 18 states and the District of Columbia have set their minimum age at 21.
Raising the federal minimum age requires an act of Congress, and the cause has attracted bipartisan support, with one proposed bill co-sponsored by Republican Senate Majority Leader Mitch McConnell.
- Reprieve for industry? -
Vaping is increasingly popular among youth, with a government survey this week finding that more than five million middle and high school students reported using e-cigarettes in the past 30 days, an all-time high.
Youth vapers overwhelmingly chose flavors like mint, mango, cream, fruit and cucumber, unlike people who are trying to quit smoking and turn to tobacco-flavored pods.
The proposed flavor ban has caused an outcry among vaping businesses, who argue they strictly ID their customers to confirm their age.
White House advisor Kellyanne Conway told reporters earlier this week vape shops may be exempted, leaving open the possibility that outlets like gas stations and convenience stores might be the ones affected by new regulations.