A recent investigation conducted by the BBC has concluded that an e-cigarette flavoring purchased in Northeast England contained a potentially harmful chemical that has been associated with the lung condition known as “popcorn worker’s lung.”

The British television program, Inside Out, purchased four liquid refills for the e-cigarettes and sent them for laboratory testing. While three of the refills came back without indication of harmful chemicals, the fourth (a butterscotch flavoring) contained a chemical called diacetyl.

Diacetyl is a yellow/green liquid with an intense butter flavor. The chemical occurs naturally in alcoholic beverages, but is also used as a food additive to give foods a “buttery” flavor.

Diacetyl recently gained some notoriety when workers in factories manufacturing the flavoring contracted bronchiolitis obliterans, a rare but serious lung condition.  The concern is that the flavoring may be hazardous and cause the disease when heated and inhaled over long periods of time.

After publication of the investigation, the e-cigarette manufacturer pulled the refills from store shelves and there is currently no report indicating that other companies, or flavorings, contain such chemicals.

The FDA has yet to regulate e-cigarettes marketed for consumption by the general public, although a mechanism to control these products is currently in the works. The FDA has issued a proposed rule seeking to extend its current authority over tobacco products to cover additional products meeting the legal definition of a tobacco product, including e-cigarettes. The comment period on the proposed rule has closed, but it is unclear when the rule will come into effect.

Until FDA passes this rule, e-cigarettes available to consumers for personal use will remain largely unregulated. Manufacturers and retailers of these products would do well to self-police these products to ensure that chemicals, like diacetyl, are not present in their flavorings. While the FDA may not independently regulate these products, this does not mean that companies selling the products are immune from lawsuits based on alleged injuries stemming from use of the products. It is not outside the realm of possibilities that plaintiffs’ attorneys may use reports, like the informal BBC study, as the next fodder for class action litigation.