Reuters reported a small test tube experiment examining the effect of e-cigarette flavoring chemicals on bronchial epithelial cells “found that both chemicals induced hundreds of genetic changes in the cells,” and “impaired the ability of the cells to function properly.” The chemicals studied were diacetyl “and its ‘chemical cousin’ 2,3-pentanedione.” Study co-author Joseph Allen, from the Harvard T.H. Chan School of Public Health explained that while “these flavoring chemicals are what we call Generally Regarded As Safe (GRAS)” for the ingestion pathway, “they have not been tested for inhalation safety.” Moreover, he said, “these flavoring chemicals…can cause severe lung disease,” when inhaled. Allen noted that “some of the newer e-cigarette companies like Juul are starting to advertise that their products do not contain (these chemicals).” The study was published in Scientific Reports.

From the news release of the American Association for Justice.