Cotton candy, cupcakes, and tutti frutti conjure carefree days as a kid, but a new study shows chemical flavorings by such yummy names are used to lace e-cigarettes and can cause severe lung disease.
Researchers at Harvard T.H. Chan School of Public Health tested 51 types of flavored e-cigarettes and refill liquids that they considered appealing to young users.
They looked for the chemicals diacetyl, acetoin, and 2,3-pentanedione, which have been linked to serious respiratory problems in workers. Diacetycl has been linked to a serious condition called "popcorn lung" which affected workers who inhaled artificial butter fumes at microwave popcorn factories.
The scientists tested for the chemicals by inserting an e-cigarette into a sealed chamber attached to a lab-built device that drew air through the e-cigarette for eight seconds at a time and then "rested" for 15 or 30 seconds between each draw. Then they analyzed the air streams and found that at least one of the three chemicals was detected in 47 of 51 flavors tested.
"One of three flavoring chemicals was found in 92 percent of the e-cigarettes we sampled and these chemicals are of interest because of what we know about the associations of inhaling these chemicals and severe, irreversible lung disease that occurred in popcorn workers over a decade ago," lead study author Joseph Allen told CBS News.
Diacetyl was found in more than 75 percent of flavored electronic cigarettes and refill liquids that were analyzed by the researchers. What's more, they found that levels of diacetyl were higher than the laboratory limit of detection in 39 of the flavors tested.
Acetoin showed up in 46 e-cigarette and liquid flavors; and 2,3-pentanedione was detected in 23 of the flavors.
There are more than 7,000 varieties of flavored e-cigarettes and e-juices, nicotine-containing liquid used in refillable devices, said Allen, an assistant professor in the Department of Environmental Health. The flavors analyzed by the scientists that came up positive for these chemicals include: Cotton Candy, Tutti Frutti, Cupcake, Fruit Squirts, Waikiki Watermelon, Double Apple Hookah, Blue Water Punch, Oatmeal Cookie and Alien Blood.
The study is published in the journal Environmental Health Perspectives.
The impact of e-cigarettes on health is still not totally clear, but Allen said the Occupational Safety and Health Administration (OSHA) has warned workers for years about the risks of diacetyl. Inhaling the chemical is associated with "popcorn lung," officially known as bronchiolitis obliterans, a respiratory condition that causes damage and inflammation to the airways and can be fatal.
Pulmonary specialist Dr. David Beuther said, "The presence of that chemical [diacetyl] is concerning enough for me to be stronger with my patients when we're talking about the unknown safety hazards of e-cigarettes."
"Bronchiolitis obliterans is irreversible. You can't take it back," said Beuther, an associate professor of medicine at National Jewish Health, one of the country's top respiratory hospitals. He said the disease leads to the need for a lung transplant.
Acetoin is also linked with "popcorn lung," according to the study.
The chemical 2,3 pentanedione has caused lung and brain damage in rats, according to the National Institute for Occupational Safety and Health.
Some e-cigarette users believe the products help them transition away from smoking regular cigarettes, but other studies have suggested they might provide a gateway to smoking for others. The products are not currently regulated by the FDA. The agency has issued a proposed rule to include e-cigarettes under its authority to regulate certain products that contain tobacco and nicotine, said Allen.
Beuther told CBS News he's particularly concerned about teens and young adults using e-cigarettes. He says that lungs are not fully developed until about age 25 and that vaping could lead to silent damage. Also, smaller people, and perhaps some women, may be exposed to a higher concentration of a given material compared to a larger man, for example, he said.
According to the CDC, there are an estimated 2.5 million teen e-cigarette users. Use among both high school and middle school students tripled in one year. Youth use of e-cigarettes has also now surpassed youth cigarette smoking.
"That's a startling number of kids," said Allen.
Children can also easily buy e-cigarettes online, according to a March 2015 study published in the Journal of JAMA Pediatrics.
Allen said a lot of e-cigarette research has focused on nicotine. But this and future studies are beginning to focus on other potentially risky chemicals in the products, too.
A 2014 study found that aerosol from e-cigarettes with a higher voltage level contains more formaldehyde, another carcinogen with the potential to cause cancer, according to the American Lung Association.
Dr. Laura Crotty Alexander, a spokesperson for the American Thoracic Society and an assistant clinical professor of medicine at the University of California at San Diego, told CBS News that education is needed so that people - kids especially - know that e-cigarettes are not harmless.
"Kids and adults both really believe it's water vapor and it's safe," said Crotty Alexander, who is also a staff physician at the VA San Diego Healthcare System. She added that e-cigarette companies run misleading online ads saying they're "clean" vapors.
"The study is yet another scary indicator of the chemicals that are contained in these drug delivery devices that are going to end up causing significant lung disease," she said.