Waste anesthetic gas exposure and controls

September 24, 1984

Donna Denholm, A.H.T.
[Recipient address omitted]

Dear Ms. Denholm:

This is in response to your request for information on the hazards of exposure to waste anesthetic gases, particularly fluothane and its possible association with reproductive effects.

Fluothane, also known as halothane, is a commonly used anesthetic agent that is often mixed with nitrous oxide for inhalation anesthesia. Current scientific evidence obtained from human and animal studies suggest that chronic exposure to anesthetic gases increases the risk of both spontaneous abortion and congential abnormalities in offspring among female workers and wives of male workers.

In March 1977, the National Institute for Occupational Safety and Health (NIOSH) published "Criteria for a Recommended Standard: Occupational Exposure to Waste Anesthetic Gases and Vapors" (NIOSH Publication No. 77-140). This document contained a recommendation that occupational exposure to halogenated anesthetic agents such as halothane be kept below 2 parts per million (ppm), based on the weight of the agent collected from a 45-liter air sample by charcoal adsorption over a sampling period not to exceed one hour. When used in combination with nitrous oxide, NIOSH believes that levels of halothane well below 2 ppm are achievable. By controlling the nitrous oxide concentration to 25 ppm during anesthetic administration, levels of the halogenated agent will be approximately 0.5 ppm.

OSHA currently has no standard covering halothane exposure, however, we do recognize the potential hazards associated with its use in the workplace. Anesthetic delivery systems should be equipped with scavenging devices to collect all waste gases. Exposures can be further minimized through the use of proper work practices and ventilation. NIOSH also recommends that periodic air monitoring be conducted and that a medical surveillance program be initiated in the form of preplacement and annual physical examinations.

Enclosed is an except from Patty's Industrial Hygiene and Toxicology, Volume 2B, 3rd edition which briefly discusses fluorocarbon exposure hazards in the health professions. For a more detailed discussion, you may wish to read the NIOSH criteria document mentioned above; it is available for viewing in our [San Francisco Area Office].

If we may be of further assistance, please do not hesitate to write or call us at [(415) 703-5210].

Sincerely,
DEAN IKEDA
Regional Industrial Hygienist

[Corrected 10/22/2004. See OSHA's Waste Anesthetic Gases page for additional information and a link to the NIOSH 77-140 publication on the "Possible Solutions" sub-page.]