Anesthetic Gases

Updated July 1, 2024

Assay Technology anesthesia delivery
Anesthesia  Delivery
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Anesthetic gases and vapors that leak into the surrounding room are considered waste anesthetic gases (WAGs). If equipment is not set up or functioning properly or if the WAG is not properly exhausted or captured via scavenging, or if ventilation not adequate, healthcare workers, researchers, and veterinary staff may be exposed to WAGs. This exposure creates a risk of potentially developing adverse health effects.

Environmental Health & Safety (EH&S) provides the Anesthetic Gases: Safe Use Guidelines to help users of anesthetic gases understand the potential health effects from exposure and provide guidance to minimize potential exposures.

Exposure to WAGs

Managers, supervisors, principal investigators, and responsible parties ensure the safety of workers, patients, researchers and research subjects by implementing safe work practices that control exposure to WAGs, including training personnel, and ensuring machines, equipment, and ventilation systems used with anesthetic gases are maintained and inspected on a regular basis.

Potential exposure to WAGs at UW could occur in the following settings:

  • UW Medicine operating rooms or other clinical applications with anesthesia
  • School of Dentistry facilities and UW Medicine-affiliated dental clinics
  • Department of Comparative Medicine (DCM) facilities (vivaria)
  • Washington National Primate Research Center (WANPRC) facilities
  • Research laboratories working with animals

Exposure to nitrous oxide and halogenated anesthetic gases can result in reproductive, neurological, psychological, and other health effects. 

Exposure control methods

Methods to control exposure to WAGs include the following:

Engineering controls: Includes general and local exhaust ventilation, scavenging systems, and key fill bottle adapters

Work practices: Document safe work practices in standard operating procedures that include transporting chemicals safely, conducting leak testing, pre-anesthesia checkout, preventive maintenance of machines and systems.

Administrative controls: Train all personnel before starting work in hazard awareness, prevention, and controls used to prevent exposures to anesthetic agents and WAGs.

Personal protective equipment: Standard personal protective equipment (PPE) worn in a clinical or laboratory setting must be worn when working with anesthetic agents; however, exposure to WAGs is not effectively reduced by gloves, goggles, and surgical masks.

Review the Anesthetic Gases: Safe Use Guidelines for information on implementing exposure control methods.

What you can do to stay safe

  • Review the roles and responsibilities listed in the Anesthetic Gases: Safe Use Guidelines.
  • Provide the required site-specific training on hazard communication and exposure risk mitigation strategies.
  • Implement exposure control methods.
  • Document work practices in standard operation procedures.
  • Perform leak testing, pre-anesthesia checkout, and preventive maintenance of machines/systems.
  • Properly dispose of expired or unwanted anesthetic gas or liquid containers, used charcoal canisters, and gas canister/cylinders.​

Emergency response and reporting

If a spill or release occurs, stop work.

  • For large spills, evacuate the area and call 9-1-1 on any campus phone for help, or follow your facility-specific procedures for chemical spill response.
  • If an exposure occurs, follow the procedures in the EH&S posters for Spill Response and Exposure Response.

Refer to the Anesthetic Gases: Safe Use Guidelines for more information on spill cleanup and exposure incidents. For questions on spill cleanup, contact EH&S Spill Advice at 206.543.0467.

Report all accidents and incidents to the UW Online Accident Reporting System (OARS) within 24 hours; however, some incidents require immediate notification.

UW Medicine personnel follow UW Medicine incident reporting procedures.

Services available

Environmental Health & Safety (EH&S) provides the following services:

  • Assist University departments, units, and organizations with training personnel on the hazards of anesthetic gases, engineering controls, safe work practices, procedures to avoid exposures, and proper PPE to wear.
  • Reviews ventilation in research spaces where anesthesia will be used.
  • Conduct personal or area air monitoring and testing as needed.
  • Collect expired or unwanted anesthetic gas or liquid containers and used charcoal canisters.
  • Consult on leak testing as needed.
  • Evaluate anesthetic gas SOPs, gas use, systems, and potential personnel exposures.


Call EH&S at (206) 543-7388 for information on:

  • Exposure concerns to anesthetic gases
  • Leak testing
  • Review ventilation in spaces where anesthesia will be used
  • Air monitoring

Call EH&S Spill Advice at (206) 543-0467.

Contact UW Employee Health Center to consult with an occupational medical professional regarding anesthetic gas exposures.


One of the principal goals of general anesthesia is to prevent patients, both human and animal, from feeling pain during surgery. A common method of anesthesia is the purposeful inhalation of a gas that is known to provide general sedative effects and/or induce unconsciousness. These gases can be separated into two categories: Halogenated anesthetic gases/vapors and nitrous oxide. These may be administered in combination to produce surgical levels of anesthesia. Halogenated anesthetic gases/vapors and nitrous oxide are also commonly used during veterinary care or experiments in animal research.

Frequently asked questions


Environmental Health & Safety Contact

(206) 543-7262