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Worker Health Study Summaries

Research on long-term exposure

Toll Collectors and Tunnel Officers (Carbon Monoxide)

NOTE: This page is archived for historical purposes and is no longer being maintained or updated.
NOTICE: These are NIOSH Archive Documents, and may not represent current NIOSH Policy. They are presented here as historical content, for research and review purposes only. This collection of Worker Notification Materials and any recommendations made herein are relevant for specific worker populations. The results do not predict risk for a given individual. The results may not be universally applicable.

1/17/1991

Study Background

NIOSH studied toll collectors and tunnel officers for exposure to carbon monoxide.

NIOSH took air samples of carbon monoxide (CO) for a health study on the effects of CO exposure.

Table 1 Part A: Lincoln Tunnel - Toll Collectors

Summary of Air Sampling Results for Carbon Monoxide (CO) taken September 10-13, 1990.

Work
Shift*
Number of Samples Average Level Over Shift** Range** Highest 15-Minute Average Range Average Peak*** Range***
1 10 8 ppm 3-14 ppm 29 ppm 17-50 ppm 87 ppm 42-132 ppm
2 20 10 5-15 29 14-62 81 42-175
3 25 8 3-13 22 7-38 89 27-229
All 3 Shifts 55 9 3-15 27 7-62 86 27-229

*       Work shifts as defined by PANY & NJ

**    Compare to the OSHA permissible exposure limit (PEL) of 35 ppm over an 8-hour workshift.

***  Compare to the OSHA peak (or ceiling) limit of 200 ppm.

Table 1 Part B: Lincoln Tunnel - Tunnel Officers

Summary of Air Sampling Results for Carbon Monoxide (CO) taken September 10-13, 1990.

Work
Shift*
Number of Samples Average Level Over Shift** Range** Highest 15-Minute Average Range Average Peak*** Range***
1 3 9 ppm 4-10 ppm 53 ppm 17-96 ppm 85 ppm 55-131 ppm
2 9 8 3-13 25 8-52 50 27-94
3 6 9 5-16 28 16-47 57 44-90
All 3 Shifts 18 8 3-16 35 8-96 64 27-131

*       Work shifts as defined by PANY & NJ

**    Compare to the OSHA permissible exposure limit (PEL) of 35 ppm over an 8-hour workshift.

***  Compare to the OSHA peak (or ceiling) limit of 200 ppm.

Table 2 Part A: Holland Tunnel - Toll Collectors

Summary of Air Sampling Results for Carbon Monoxide (CO) taken September 10-13, 1990.

Work
Shift*
Number of Samples Average Level Over Shift** Range** Highest 15-Minute Average Range average peak*** Range***
1 10 5 ppm 1-8 ppm 24 ppm 11-34 ppm 95 ppm 53-161 ppm
2 13 5 2-12 19 8-30 65 24-118
3 23 5 2-12 28 6-27 68 32-156
All 3 Shifts 46 6 1-12 24 6-34 76 24-161

*       Work shifts as defined by PANY & NJ

**     Compare to the OSHA permissible exposure limit (PEL) of 35 ppm over an 8-hour workshift.

***  Compare to the OSHA peak (or ceiling) limit of 200 ppm.

Table 2 Part B: Holland Tunnel - Tunnel Officers

Summary of Air Sampling Results for Carbon Monoxide (CO) taken September 10-13, 1990.

Work
Shift*
Number of Samples Average Level Over Shift** Range** Highest 15-Minute Average Range average peak*** Range***
3 4 7 4-10 ppm 42 25-66 209 46-372

*       Work shifts as defined by PANY & NJ

**     Compare to the OSHA permissible exposure limit (PEL) of 35 ppm over an 8-hour workshift.

***  Compare to the OSHA peak (or ceiling) limit of 200 ppm.

Table 3: George Washington Bridge - Toll Collectors

Summary of Air Sampling Results for Carbon Monoxide (CO) taken September 10-12, 1990.

Work
Shift*
Number of Samples Average Level Over Shift** Range** Highest 15-Minute Average Range Average Peak*** Range***
1 10 1 ppm 0-11 ppm 5 ppm 0-11 ppm 25 ppm 1-62 ppm
2 10 2 0-4 4 0-10 12 4-27
3 14 2 0-6 5 1-10 21 5-117
All 3 Shifts 34 1.5 0-6 5 0-11 19 1-117

The air inside the ventilated booths has about one quarter (25%) the CO as the air outside the booths.

*       Work shifts as defined by PANY & NJ

**     Compare to the OSHA permissible exposure limit (PEL) of 35 ppm over an 8-hour workshift.

***   Compare to the OSHA peak (or ceiling) limit of 200 ppm.

Table 4: Goethals Bridge - Toll Collectors

Summary of Air Sampling Results for Carbon Monoxide (CO) Inside Unventilated Booths taken September 13, 1990.

Work
Shift*
Number of Samples Average Level Over Shift** Range** Highest 15-Minute Average Range Average Peak*** Range***
1 4 4 ppm 1-8 ppm 20 ppm 3-36 ppm 59 ppm 4-118 ppm
2 7 10 5-14 51 16-31 73 47-112
3 5 9 6-12 22 14-32 59 35-70
All 3 Shifts 16 7 1-14 22 3-36 65 4-118

The concentration of CO inside the unventilated booths was about 16% higher than the concentration outside the booths. (The concentration of CO inside the George Washington Bridge booths, which are ventilated, was about 75% lower than the concentration outside the booths).

*      Work shifts as defined by PANY & NJ

**    Compare to the OSHA permissible exposure limit ( PEL) of 35 ppm over an 8-hour workshift.

***  Compare to the OSHA peak (or ceiling) limit of 200 ppm.

Explanation

NIOSH took air samples of carbon monoxide (CO) for a health study on the effects of CO exposure.

ppm: "ppm" means "parts per million." It is a measure of the concentration of a substance in air. For example, 1 ppm of CO means 1 "part" of CO for every one million "parts" of air.

Average level over shift: the concentration of CO averaged over the work shift.

Range: the lowest and the highest concentration of CO for each shift The range is shown for three measurements: 1) the average over the shift, 2) the average over 15 minutes, and 3) the average peak.

Highest 15-minute average: the average of all the highest 15-minute concentrations recorded during each shift.

Average peak: "peak" means the highest concentration recorded for an air sample. The average peak is the average of all the peaks recorded over each shift.

What Does This Mean?

The Occupational Safety and Health Administration (OSHA) has two permissible exposure limits (PELs) for CO exposure. Exposures may not be over 35 ppm averaged over 8 hours and may never be over 200 ppm.

NIOSH's recommendations are the same as OSHA's legal standard.

OSHA does not have legal authority over the PANY & NJ because it is a state agency, but PANY & NJ voluntarily complies with OSHA regulations.

One of the samples was higher than the OSHA PEL for peaks — 229 ppm. We don't know if this represented a routine exposure.

One of the samples was higher than the OSHA PEL for peaks — 372 ppm. We don't know if this represented a routine exposure.

Motor vehicle exhaust contains CO. CO exposures to toll collectors have decreased over the years as vehicle emissions have decreased and ventilation has increased. PANY & NJ varies the air ventilation in the tunnels depending on traffic flow.

Currently, there are no generally recognized health effects from breathing CO at the levels seen in the survey. The first sign of CO poisoning from exposure to higher levels (over 100 ppm) is usually a headache.

However, there is concern that the higher CO levels present in tunnels in the past may have caused more serious health effects. A previous NIOSH study found deaths from heart disease a third higher than expected in tunnel officers.

Any Questions?

If you have any questions about the exposure survey, call NIOSH's toll-free number: 800-356-4674.

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES • Public Health Service
Centers for Disease Control • National Institute for Occupational Safely and Health
Cincinnati, Ohio 45226

For more information, call the NIOSH toll-free number: 800-356-4674.

Additional Resources

Stern FB., Halperin WE., Hornung RW, Ringenberg VI, McCammon CS. "Heart Disease Mortality Among Bridge and Tunnel Officers Exposed to Carbon Monoxide. " American Journal of Epidemiology. Vol. 128, No. 6, 1276-1288, 1988.

Herbert R., Szeinuk J., O'Brien S. "Occupational Health Problems of Bridge and Tunnel Officers." Occupational Medicine: State of the Art Reviews. Vol. 16, No. 1, 51-64, 2001.

 

 
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