Specifications

i
SUMMARY
Nurses’ exposure to formaldehyde in the dirty core and nitrous oxide in labour and delivery
rooms was measured on July 10 and July 26 to August 2, 2001, using personal and
environmental sampling methods, at Langley Memorial Hospital (LMH) in British Columbia.
The project was funded by the Workers’ Compensation Board (WCB) of British Columbia (BC)
as part of a Chemical Exposure Risk Assessment for the South Fraser Health Region.
All formaldehyde samples taken in the dirty core were below the Workers’ Compensation Board
of British Columbia 8 hr exposure limit of 0.3 ppm and the ceiling limit of 1 ppm.
Instantaneous personal measurement of nurse exposure to nitrous oxide in the labour and
delivery rooms varied between 0 and 566 ppm. Full shift average exposures for the nurses
varied from 1.3 ppm to 15.1 ppm.
Conclusions:
Formaldehyde:
• Although worker exposure to formaldehyde in the dirty core area did not exceed WCB of BC
exposure limits, exposures must be maintained at levels as low as reasonably achievable
below the exposure limit (designated as a suspected human carcinogen).
Nitrous oxide:
• Average exposures were below the 12 hr limit of 12.5 ppm with the exception of one nurse
• 5 nurses’ personal data logged samples exceed the 5X excursion limit of 125 ppm.
• The limit set by the WCB of BC of an 8 hour TWA of 25 ppm is attainable at this point in
labour and delivery, where nitrous oxide is self-administered, but the 5X excursion limit of
125 ppm is not.