Permissible Exposure, OSHA, & Studies

“Field studies of environmental tobacco smoke indicate that under normal conditions, the components in tobacco smoke are diluted below existing Permissible Exposure Levels (PELS.) as referenced in the Air Contaminant Standard (29 CFR 1910.1000)…It would be very rare to find a workplace with so much smoking that any individual PEL would be exceeded.” –Greg Watchman, Acting Assistant Secretary, OSHA, To Leroy J Pletten, PHD

Air quality tests from around the globe show that environmental tobacco smoke (ETS) or secondhand smoke (SHS) levels in real-world environments are significantly lower than OSHA’s permissible levels, even in unfiltered/unventilated bars. Our proposal, which includes ventilation and filtration, would actually bring the air in exempted indoor locations well within the EPA range of good to moderate air quality.

University of Washington Study
This University of Washington study tested 20 Missouri smoking establishments and found that secondhand smoke levels in ALL 20 bars & restaurants tested ranged from 110 to 877 times safer than OSHA workplace air quality standards require.

Johns Hopkins Study
This Johns Hopkins University study shows secondhand smoke levels at bars and restaurants in Baltimore, MD are 29.6 (500 divided by 16.9) to 238 (500 divided by 2.1) times safer than the OSHA nicotine PEL.

BMJ Study
This British Medical Journal study tested European smoking establishments and found that secondhand smoke levels in ALL of the bars & restaurants tested ranged from 19-122 µg/m3, 4 to 26 times safer than OSHA workplace air quality standards require (nicotine PEL < 500 µg/m3). Yet the authors of the study conclude their results show smoking should be banned in more public places.

The American Cancer Society Study
This ACS-sponsored study tested Western New York smoking establishments and found that secondhand smoke levels in all of the bars & restaurants tested ranged from 539 – 940 nanograms (0.539 – 0.940 micrograms) which is 532 to 928 times safer than OSHA workplace air quality standards require (less than 500 micrograms). Yet the author of the study concludes secondhand smoke should be banned in more public places.

The St. Louis Park, MN Study
This St. Louis Park, MN. Environmental Health Dept study tested 19 Minnesota smoking establishments and found that secondhand smoke levels in ALL 19 of the bars & restaurants tested ranged from 1 – 32.5 µg/m3 which is 15 to 500 times safer than OSHA workplace air quality standards require (PEL less than 500 µg/m3).

Additional Studies

Additional studies have shown any other substances related to secondhand smoke in smoking environments are within OSHA or NIOSH limits, even without filtering.

In this IARC study, secondhand smoke was analyzed in the following places (it’s not mentioned if any had filtered ventilation systems. If not, SHS levels would be far lower):

  • A 18m3 controlled smoking chamber
  • A living quarters
  • A tavern
  • A discoteque
  • A home

For each, the maximum amounts of each secondhand smoke substance detected are all under the limit when paired with OSHA’s eight hour permissible exposure limit (PEL).

TWA = 8 hour permissible exposure limit. The TWAs listed are the minimum between OSHA, NIOSH or Material Safety Data Sheets.

Important Note: Per Table 1.1 of the IARC study linked above, the measured substances are not typical average concentrations, but represent the higher end of the exposure scale. Averaging would significantly reduce the recorded substance amounts.

Nicotine in Discotheque = 120 µg/m3
Nicotine TWA = 500 µg/m3
500 µg/m3 >> 120 µg/m3 (below TWA)
Carbon Monoxide in Discotheque
= 22.1 ppm
Carbon Monoxide TWA = 35 ppm
35 ppm >> 22.1 ppm (below TWA)
Benzene in 18m3 chamber = 30 µg/m3
Benzene TWA 1 ppm = 3.19 mg/m3
3190 µg/m3 >> 30 µg/m3 (below TWA)
Formaldehyde in 18m3 chamber
= 143 µg/m3
Formaldehyde TWA 0.75ppm=0.92 mg/m3
= 920 µg/m3 >> 143 µg/m3 (below TWA)
1,3-Butadiene in 18m3 chamber
= 40 µg/m3
1,3-Butadiene TWA 1.0ppm = 2.21mg/m3
= 2210 µg/m3 >> 40 µg/m3 (below TWA)
Acetaldehyde in 18m3 chamber
= 268 µg/m3
Acetaldehyde TWA = 360 mg/m3
= 360,000 µg/m3 >> 268 µg/m3 (below TWA)
Isoprene in 18m3 chamber = 657 µg/m3
Isoprene TWA = 2ppm x 2.79 =5.58mg/m3
= 5580 µg/m3 >> 657 µg/m3 (below TWA)
Styrene in 18m3 chamber = 10 µg/m3
Styrene TWA = 215 mg/m3
= 215,000 µg/m3 >> 10 µg/m3 (below TWA)
Catechol in 18m3 chamber = 1.24 µg/m3
Catechol TWA = 20 mg/m3
= 20,000 µg/m3 >> 1.24µg/m3 (below TWA)
3-Ethenyl pyridine in 18m3 chamber
= 37.1 µg/m3
3-Ethenyl pyridine TWA = N/A
Found in alcohol beverages
Ethylbenzene in 18m3 chamber
= 8.5 µg/m3
Ethylbenzene TWA = 435 mg/m3
= 435,000 µg/m3 >> 8.5 µg/m3 (below TWA)
Pyridine in 18m3 chamber = 23.8 µg/m3
Pyridine TWA = 15 mg/m3
= 15,000 µg/m3 >> 23.8 µg/m3 (below TWA)
Toluene in 18m3 chamber = 54.5 µg/m3
Toluene TWA = 375 mg/m3
= 375,000 µg/m3 >>54.5 µg/m3 (below TWA)
Limonene in 18m3 chamber= 29.1 µg/m3
Limonene TWA = 165.6 mg/m3
= 165,600 µg/m3 >> 29.1 µg/m3 (below TWA)


This study on smoking in casinos attempted to claim SHS was elevated to harmful levels for employees. It draws a conclusion in the abstract that “Casino ventilation and air cleaning practices failed to control secondhand smoke PM2.5.”

However, the details of the study reveal otherwise. Table 2 shows that only two of the eight casinos listed exceeded the EPA’s scale. Yet non-smoking locales can also have PM 2.5 levels significantly higher than 35.4 µg/m3, according to additional studies, because cooking and dust are other PM 2.5 sources. Not only that, but this study didn’t even know what, if any, ventilation systems most of its subjects were using:

“We have no information on the air cleaning devices for any casinos except those reported for the 3 casinos in the NIOSH Las Vegas study: Bally’s Las Vegas had triple the filtration efficiency of either Paris or Caesar’s Palace casino.”

Let’s put aside for a moment that the authors’ conclusion was that filtration was ineffective despite not knowing anything about what, if any, filtration systems were being used. The authors also failed to mention that according to their own results, all three of these casinos were still within the EPA healthy range of 35.4 µg/m3. This strongly suggests the air cleaning was effective – yet the authors somehow managed to reach the exact opposite conclusion.

Additionally, this study was done around nine years ago. Filter and ventilation technology has been continuously improving since then. Our common-sense solution to the ban will ensure that PM 2.5 levels meet or exceed EPA air quality standards for good to moderate air, and that the air within exempted locations is within the EPA’s healthy range.