CARBON MONOXIDE IN THE WORKPLACE
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365-BSA-01-IMOT © 2024, Workplace Safety & Prevention Services (WSPS)
1 877 494 WSPS (9777) | 905 614 1400 | WSPS.CA
How can exposure to carbon monoxide occur in the workplace?
There are two types of exposure:
acute or short-term exposure
chronic or long-term exposure
Acute exposures often occur during accidents or sudden releases of carbon monoxide. These conditions
are usually short-lived but can produce high concentrations of carbon monoxide. Chronic exposures
are more typical of workplace exposures to carbon monoxide. These are generally more predictable
and controllable. Depending upon the concentrations generated, these exposures may produce no
signs or symptoms under normal circumstances. Serious problems may occur when the control of low-
level sources breaks down and higher levels are then produced. This may happen with fuel-burning
equipment or fuel-powered engines and off gasing of carbon containing material such as wood pellets.
ASSESS: How can concentrations be determined?
Since carbon monoxide has no odour and is not visible, the only way to determine its presence and
concentration is to sample or monitor the air. The purposes of monitoring (sampling on a regular basis)
workplace air are to:
evaluate exposure
evaluate effectiveness of control measures
provide warning about excessive emissions
Several technologies are available for measuring carbon monoxide. These can be classified as grab
samplers, long-term samplers and continuous samplers. Each technology has its own strong and
weak points.
Grab samplers are similar to taking a picture of a situation. The result is valid only at the time the
sample is taken. These devices are inexpensive and easy to use. They provide almost instantaneous
indication of a problem. Grab samplers do not usually provide alarms, and they are not very accurate.
Long-term samplers provide an average of the overall concentration present during a period of time.
This information is useful for determining time-weighted average exposures or emission rates. As with
grab samplers, no alarm is usually given during the sampling period.
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