Revision 6/2020


Anesthetic vapors that leak into the surrounding room during animal surgeries are called Waste Anesthetic Gases (WAG). It is estimated that more than 250,000 health care professionals who work in hospitals, operating rooms, dental offices and veterinary clinics, are potentially exposed to waste anesthetic gases and are at risk of occupational illness. The waste anesthetic gases and vapors of concern involved in animal surgery are liquid halogenated inhalation agents (vapors) such as halothane, enflurane, isoflurane, and desflurane. Some potential effects of exposure to waste anesthetic gases are nausea, dizziness, headaches, fatigue, and irritability, as well as sterility, miscarriages, birth defects, cancer, and liver and kidney disease, among operating room staff or their spouses (in the case of miscarriages and birth defects). Lab workers should be aware of the potential effects and be advised to take appropriate precautions.


Passive Anesthesia Scavenging Guidelines for Rodent Satellite Surgery Areas


The following requirements apply to rodent anesthesia situations and assumes the use of a non-rebreathing circuit.

Induction Chambers

  • Household plasticware not permitted
  • Vent chamber into ducted biosafety cabinet, fume hood or charcoal canister
  • Gaskets in good condition and inspected prior to every use
  • Purge induction box for 10 seconds before opening

Hoses and Connections

  • Connections must be made with commercial fittings that are tight fitting
  • Tape not permitted
  • Replace hoses if they fail a leak check, visibly damaged or soiled.
  • Label anesthesia rig with hose replacement date
  • Leak check system and inspect components monthly  
  • Date system with last leak check date


  • Secure with a frame, pole mount or equivalent restraint
  • Calibrate yearly
  • Fill inside a fume hood or use keyed refill tool

Nose Cones 

  • Use nose cones that enclose both the nose and mouth
  • Use nose cones that provide a tight fit (for example angled or oval with membrane)
  • Replace membranes (if used) when slit is too large or if cracking is observed

Charcoal Scavenging Canister

  • Support canister such that discharge openings are not occluded
  • Weigh after each use and track weight gain. If canister does not gain weight review system for leaks and replace canister.  Replace per manufacturer's guidelines.
  • Dispose of used canister through hazardous waste disposal system

General Surgery Area Requirements

  • Lab ventilation of 4 air-changes per hour (non-recirculating)



Passive Anesthesia Scavenging Guidelines