New e-cig risk assessment uses the wrong standard

Many people have asked me what I thought about the report "Peering through the mist: What does the chemistry of contaminants in electronic cigarettes tell us about health risks?" that being publicized by the e-cig advocacy group CASAA.

This paper uses  the same approach to risk assessment that I remember from risk assessments done of secondhand smoke years ago by tobacco industry apologists that concluded that secondhand tobacco smoke could not produce any adverse health effects.

The first problem with this study is that it compares levels of various toxins in e-cigs with threshold limit values (TLVs) which have been published by the American Council of Government Industrial Hygienists using that are generally viewed as not health protective.  In addition, as noted in the report, TLVs are for occupational exposures.  Occupational exposures are generally much higher than levels considered acceptable for ambient or population-level exposures. Occupational exposures also do not consider exposure to sensitive subgroups, such as people with medical conditions, children and infants, who might be exposed to secondhand ecigarette emissions.  Finally, even when setting allowable occupational exposures, regulatory agencies like OSHA often establish tighter standards than TLVs, and often those tighter levels have been criticized as not being health protective.

The report itself also notes that "the quality of much of the data that was available for this assessment was poor," which is an ongoing problem with doing this kind of risk assessment.  Some of these problems are due to the poor quality of some of the studies and others are due to the poor quality control of the ecigs themselves.

The analysis also ignores the high levels of ulttrafine particles e-cigs generate that can trigger inflammatory processes and trigger heart attacks and respiratory problems.

Carl Phillips, CASAA's Scientific Director, who contributed "frank discussions of relevant scientific matters," is a long-time tobacco industry apologist.

So, this paper is not something prudent decisionmakers should use to make policies about ecigarettes or involuntary exposure to secondhand ecig emissions.



Cancer Risk is 2 carcinomas in 10,000 at Risk just for HCHO


This guy inappropriately uses TLVs when EPA risks for the chemicals should be used.  For example, Schripp found 16 ug/m3 of formaldehyde in an 8 m3 chamber from 1 e-cig.  That's a risk of 2 in 10,000 for squamous cell carcinoma, or 200 times de minimis risk.  EPA's IRIS data base should be used for every chemical in the E-liquid.  I pointed out in comment to FDA, that much work needs to be done.  The World Health Organization stated that some manufacturers have claimed that E-cigarettes can be used legally in environments where smoking is prohibited. WHO strongly recommends that E-cigarettes not be exempted from ‘clean air’ laws, which restrict the places in which cigarette smoking is allowed, until adequate evidence is provided to assure regulatory authorities that use of the product will not expose nonusers to toxic emissions.  Finally, in comments to the US Department of Transportation [Docket No. DOT-OST-2011-0044, RIN No. 2105-AE06, Smoking of Electronic Cigarettes on Aircraft, I wrote in part the following: Repace Comments:It is obvious that E-cigarettes emit an aerosol when puffed.  Aerosol in the outdoor air (PM2.5) is a regulated air pollutant with no known threshold for acute and chronic effects on the cardiovascular system.  It may also contain ultrafine particles, and does contain VOCs of various sorts, including various unregulated chemicals of unknown composition, plus glycols and nicotine, which is a known toxin.  It is also known that air pollution affects people differently depending upon their health status and sensitivity.  The hypothesis being advanced by proponents is that there are no acute or chronic health effects or air pollution impacts if these devices are used in currently smoke-free areas.  This hypothesis is unsubstantiated by research, and E-cigarettes remain unregulated products of mostly unknown composition.

 An appropriate research program would start by collecting multiple samples of each of the 2 dozen or more brands currently being marketed and analyzing the E-liquids in them.  Next, multiple tests would be run on the devices when they are smoked under controlled circumstances in an experimental chamber to determine emission factors for each of the components of toxicological interest, including carcinogenic potency.  In this manner, the standard mass-balance model can be used to predict their concentrations in occupied spaces.  Next, panels of healthy nonsmokers and sensitive nonsmokers would be employed to test the odor, irritation, and cardiorespiratory impacts of exposure to E-cigarette vapor, using standard butanol wheel, eye-blink, pulmonary function, and heart rate variability tests.  This would allow public policy to be based on science, rather than speculation.  Of course, such studies would involve multi-million dollar research grants and multidisciplinary researchers involved.   Then the peer-reviewed and journal-published data would be reviewed by impartial expert panels of national and international agencies. 


James Repace, President, Repace Associates, Inc. Secondhand Smoke Consultants




What did Schripp really find concerning formaldehyde?

Schripp specifically mentions in his study that formaldehyde was detected BEFORE the e-cigarette was used. And he concluded that it came from the breath of the volunteer. Because, as you probably know, formaldehyde is produced by the metabolism of each human, and such minute quantities are subsequently exhaled. Are you really suggesting that by sitting next to a person in an 8m3 room, my cancer risk will be elevated? Should we regulate that none should stay in a closed room next to another person?


Konstantinos Farsalinos, MD

Researcher, Onassis Cardiac Surgery Center

Stop misquoting Schripp findings on formaldehyde

           Some commenters disagreed with my interpretation of the Schripp et al. (2013) study. It is worthwhile reviewing Schripp et al.’s study.  In one of the first peer-reviewed studies of e-cigarette emissions from three different products in a chamber study, Schripp et al. reached the following major conclusions: that the e-cigarette is a new source of VOCs and ultrafine/fine particles in the indoor environment.  Schripp accordingly coined a new term:  “passive vaping.” They further note that the impact of e-cigarette vapor inhalation into the human lung of non-users should be of primary concern.

          Schripp et al. (2013) detected the VOCs 1,2-propanediol, various flavoring substances, and nicotine in addition to fine and ultrafine particles (FP/UFP) into indoor air when 3 different e-cigarette products were used as intended. Schripp et al. noted that the formation of formaldehyde, acetaldehyde, and methylglyoxal in the e-cigarette has been proposed on theoretical grounds but their experimental results could not differentiate between exhaled breath and e-cigarette vapors, likely due to the small number of e-cigarettes used, and the high limit of detection. In particular, they stated: "However, continuous monitoring only showed a slight increase in the formaldehyde concentration in the 8-m3  emission test chamber before and during the consumption of the three liquids (see Table 4 and Figure 2). This might be caused by the person in the chamber itself, because people are known to exhale formaldehyde in low amounts (Riess et al., 2010) and the increase was already observed during the conditioning phase(Figure 2)."

          E-cigarette promoters have seized been aggressively misrepresenting this statement, including in the comment from Konstantinos Farsalinos, who inaccurately claimed that, Schripp et al “concluded that it came from the  breath of the volunteer.”    Schripp made no such conclusion; he raised the possibility that it might be happening.

          Konstantinos (and all the others who claim that Schripp “concluded” the formaldehyde detected in the air was not due to the e-cigarettes) also ignore the data reported in Table 4 in which Schripp et al. reported 15 minute-average samples collected by SilicaGel, shows significant increases in formaldehyde (HCHO) . 8, 11 and 18 ug/m3 respectively after 1, 2, and 3 e-cigarettes were smoked, well over background (<1 ug/m3) with just the person in the chamber. Moreover, careful examination of the real-time data measured by the HCHO auto-analyzer, as reported in Figure 2, shows the background HCHO level with the test subject in chamber prior to smoking for 20 min essentially constant at 12 ug/m3 (100 ppb), then increasing over background approximately by 2.4 ug/m3 after smoking the first e-cigarette, then by 4.9 ug/m3 after the second, and finally by 9.8 ug/m3 after the third.  (The chamber was cleared between e-cigarettes).  These two different methods both clearly show that formaldehyde in the ambient air increases with e-cigarette consumption.  

         So, while the real-time data appear to show a background level with just the subject in the chamber, the time-averaged data do not, perhaps because of different limits of detection.  Most important, both methods show increasing formaldehyde  in the surrounding air with e-cigarette consumption.

          It is also important to emphasize that formaldehyde was not the only toxin delected in the air following e-cigarette use.

          Finally, Schripp et al. tested only 3 brands of e-cigarettes. However, one website lists 22 different “top brands” (CocktailNerd, 2013).  We do not know which of these Schripp et al. might have tested, if any.  Vardavas et al. (2011) noted that different manufacturers use different designs and incorporate a range of ingredients, and there is limited evidence on the actual constituents of each brand. There is no regulation of these pharmaceutical products, and active and passive users are at the mercy of the quality control and quality assurance of each of the individual overseas manufacturers.

          Despite these limitations, Schripp has debunked the claim that e-cigarettes only emit “harmless water vapor.”

          Moreover, Vardavas et al. (2011) reported “adverse physiological effects in users of e-cigarettes after 5-minute inhalation, including increases in pulmonaryimpedance, peripheral airway flow resistance, and oxidative stress among healthy individuals, similar to some of the effects seen with tobacco smoking and worthy of further investigation.”   Vardavas et al.’s study suggests that the effects of breathing e-cigarette vapors (passive vaping) may induce more severe breathing difficulties in nonsmokers.

James Repace
Repace Associates, Inc.
Secondhand Smoke Consultants.


Does e-cigarette consumption cause passive vaping?  Schripp T, Markewitz D, Uhde E, Salthammer T. Indoor Air.2013 Feb;23(1):25-31. doi: 10.1111/j.1600-0668.2012.00792.x. Epub 2012 Jul 2.

Vardavas, C.I., Anagnostopoulos, N., Kougias, M., Evangelopoulou, V., Connolly, G.N. and Behrakis, P.K. (2011) Acute pulmonary effects of using an e-cigarette: impact on respiratory flow resistance, impedance and exhaled nitric oxide, Chest, 141, 1400–1406.  <>., Best E Cigarettes Comparison.

Schripp et al.

Dear Mr Repace,

you should read the study of Schripp and Salthammer properly!

The emissions of formaldehyde did not come from the ecigarette but from the person who vaped the ecig.

Schripp et al. wrote in their study "Does e-cigarette consumption cause passive vaping?" [1] :

"This might be caused by the person in the chamber itself, because people are known to exhale formaldehyde in low amounts (Riess et
al., 2010) and the increase was already observed during the conditioning phase (Fig-ure 2)."

What Salthammer knew exactly, because he published a study in 2010 named "Formaldehyde in the Indoor Environment" [2].

At least in this study, the source of formaldehyde was the human being  - 16 ug/m3 ... is (SURPRISE!) the amount of formaldehyde a human exhales

in 90 minutes.

If you really sounding the "cancer-alarm" on this study, you should be alarmed of the risk of "Second Hand Breathing" ;)





Slight inaccuarcy

I wonder if you would care to comment on the fact that the 16ug/m3 formaldehyde result in Schripp's data, which you hold up as a wonderful example of the danger posed from one e-cig is actually the cumulative result of 3 e-cigs, as well as a noticeable increase prior to the use of any ecigs at all due to the metabolism of the participant? In fact the study author explicitly stated that "continuous monitoring showed only a slight increase in the formaldehyde concentration.... before and during the consumption of the three 'liquids'...This might be caused by the person in the chamber itself... and the increase was already observed during the conditioning phase". Formaldehyde was also below the limit of detection when the vapour was measured in a 10 litre vessel, at less than 2ug/m3, providing a strong indication that the level of formaldehyde you are so concerned about is predominantly a risk associated with sharing an 8m3 space with one or more persons, and that the use of electronic cigarettes has little effect on this.

Cherry picking a single result is pointless, stupid and does not help the credibility of your position.

Link to Schripp

This is the link to Schripp's paper.  Jim Repace