Artificial flavors added to some electronic cigarettes to give them a fruit- or candy-laced taste contain a chemical that has been linked to a lung ailment when inhaled, according to a study published Tuesday of more than 50 types of e-cigarettes.
Scientists from the Harvard T.H. Chan School of Public Health tested the contents of 51 different types of e-cigarettes for a chemical called diacetyl, which is commonly found in artificial flavorings in foods and drinks, as well as two other chemically similar flavoring compounds, 2,3-pentanedione and acetoin.
They selected a range of e-cigarettes with flavors that they thought would appeal to children and young adults, including “cotton candy,” “Waikiki watermelon,” “tutti frutti” and “oatmeal cookie.” Using a lab-built device that draws and releases air from e-cigarettes and measures the compounds they release — a technique used by the Occupational Safety and Health Administration (OSHA) — the scientists found that 39 of the 51 types of e-cigarettes tested contained diacetyl. Additionally, 47 out of 51 of the e-cigarettes — or 92 percent — contained at least one of the three flavoring chemicals.
While the U.S. Food and Drug Administration has determined that diacetyl is safe to eat, it can be extremely harmful when inhaled. In the early 2000s, after several workers at a microwave popcorn factory developed a lung disease, the National Institute for Occupational Safety and Health (NIOSH) ran tests at the factory. They discovered that inhaling the heated diacetyl found in the popcorn’s butter flavoring was linked to a condition called “bronchiolitis obliterans,” an irreversible loss of pulmonary function that can require a lung transplant if severe.
The phenomenon was dubbed “popcorn lung,” and NIOSH and OSHA discovered a strong relationship between inhaled exposure to the chemicals and obstructed airways in further testing. As a result, they set limits for how much of the flavor chemicals workers can be exposed to. The Flavoring and Extract Manufacturers Association of the United States, an industry group, released a report in 2012 that warned workers about the potential risks of exposure to the chemicals.
Asked about the study report released Tuesday, Thomas Kiklas, co-founder of the industry group Tobacco Vapor Electronic Cigarette Association (TVECA), said in an email that the organization has mandated since its formation in 2008 that “all members continually test their e Liquids” and “use only pharmaceutical grade ingredients,” among other steps.
“We are looking into who these companies are,” and the age of the liquids tested, Kiklas said.
“Workers are getting warnings about potential hazards of working with these chemicals, but we’re not seeing these warnings reaching consumers of flavored e-cigarettes,” said Joseph G. Allen, a professor of exposure assessment science at Harvard T.H. Chan School of Public Health and lead author of the study, which was published in the journal Environmental Health Perspectives (PDF).
Allen and his team were inspired to do the study after learning that electronic cigarettes come in more than 7,000 flavors. They were also aware that 1.78 million children tried e-cigarettes in 2012, according to estimates from the U.S. Centers for Disease Control and Prevention. Some 160,000 of those children had never tried regular cigarettes before, the CDC found.
“From this history of popcorn workers, and knowing that diacetyl is used in many different flavors beyond butter, we had a strong feeling that we would find this in e-cigarettes,” Allen said.
The authors of the study noted that in a review of the website and packaging for the e-cigarettes they had tested, none had offered any warnings about diacetyl or other flavor chemicals. In fact, they said, two companies stated in their branding literature that their products didn’t contain diacetyl, “yet in our testing we did find diacetyl in their product,” they wrote.
E-cigarettes are battery-powered devices that heat a nicotine-laced vapor that is inhaled, but doesn’t contain tobacco — and they have exploded in popularity in the last few years. The World Health Organization estimates that consumers spent $3 billion on them in the U.S. in 2013, and expects sales to increase to $51 billion by 2030, according to Euromonitor, a London-based research firm.
But the e-cigarette industry is not regulated the way tobacco products are. In 2011, the FDA announced its intent to regulate e-cigarettes in the same way tobacco products are regulated; in 2014, it issued a proposed rule to do so.
But as of now, the companies that make e-cigarettes don’t have to follow quality control standards, or even disclose all of the ingredients their products contain.
When asked whether there are safe levels of diacetyl or other flavor chemicals, Allen said that scientists need more information — and that this is why e-cigarettes ought to be regulated at the same level that other tobacco products are.
“Research around e-cigarettes is so new, and we don’t have any information on what is a safe level, if there is one at all,” he said.