Making a Safe Product Safer
A group of scientists led by Konstantinos Farsalinos conducted a study last September, testing 159 flavored e-liquids for the presence of diacetyl propionyl and acetyl propionyl. They found them in a majority of the samples tested, but on average at levels below thresholds set by the National Institute for Occupational Safety and Health (NIOSH).
Although these substances are approved for use in food, NIOSH has found them to cause respiratory problems in workers who inhale them in the workplace over long periods of time. They are present at high levels in cigarette smoke, and at lower levels in e-cig vapor.
The news this week is that NIOSH has responded to the study with a letter to the publication Nicotine and Tobacco Research, where the study came out, clarifying certain issues regarding levels and research subjects.
The letter does nothing to alter the main thrust of the Farsalinos group's study -- that these chemicals can be removed from e-liquids with engineering, making the problem an avoidable one. The study, says Farsalinos, should be read as an alert to the industry about an avoidable risk.
Cigarettes produce the chemicals as a by-product of the combustion of tobacco, while in the e-liquids that contain them, they are present as ingredients. This, says Farsalinos, is why they are a completely avoidable danger for manufacturers and users of vaping products.
As NIOSH and the FDA know perfectly well (but the CDC and UCSF don't want you to know), there is no such thing as a 100% risk-free substance. Safety standards are measured in terms of risk percentages. The NIOSH threshold for diacetyl propionyl and acetyl propionyl is a level that would cause respiratory dysfunction in 1 worker in 1000 who had inhaled it daily in the workplace for a period of 45 years.
Cigarette smoke produces levels of diacetyl 100 times the NIOSH threshold, acetyl 10 times higher. Sixty percent of the liquids tested by the Farsalinos group contained amounts slightly lower than the threshold, but 40% had higher levels. The highest for diacetyl was 495 times higher than the threshold, and the highest for acetyl was 22 times higher – of course these levels are unacceptable, but the broad range of levels in the liquids studied shows clearly that these are not necessary ingredients, and can be removed. If regulators ever get around to doing their job of regulating, they can simply outlaw them in e-liquid, without harming the industry a bit. They cannot do that for cigarettes.
The NIOSH letter clarifies questions about the research population they used in the tests that established the threshold. The subjects were workers, and the Institute wondered whether comparisons with consumers or with the general public were valid. They also noted that their tests assumed an elevated respiration rate during work, while the nicotine scientists seemed to assume a resting respiration rate. NIOSH also questioned the findings of one particular study regarding levels of diacetyl/acetyl in cigarette smoke.
The scientists countered by accepting the revision on respiration rate of research subjects, and by producing other studies and findings confirming their statements on levels in cigarette smoke. They also noted that the study population for questions about the substances in smoke and vapor is the smoking population, a group that faces risks not of 1/1000 but of 1/3 or 1/4. Says Farsalinos, “a risk level of 1 in 1000 developing lung dysfunction represents a tremendous benefit for smokers who have a 1 in 3-4 risk of developing chronic obstructive lung disease in their lifetime.”
The most encouraging aspect of this story is the realization that the vaping community can rely on the support of fine scientists who will alert the industry on ways to make a safe product even safer.