Fire from Waste Anesthetic Gas

​Key Learning

Surgical anesthesia of rodents creates an oxygen-enriched atmosphere and when an ignition source (e.g. electrocautery) is brought into an uncontrolled waste anesthetic gas environment, ignition happens. 

Effects of Incident

The initial effects included staff distress and an injured animal. The long term effects led to an institutional standard requiring active scavenging of waste anesthetic gases during rodent anesthesia. 


Inhalational anesthesia is a common practice in animal research facilities. The procedure often begins with a rodent being placed into an induction chamber. An oxygen/anesthesia mixture is delivered into the chamber and the rodent is anesthetized. If a surgical procedure is to be performed, the rodent is placed on a surgical table and a nose cone anesthesia delivery apparatus is positioned over rodent’s face. In a passive waste anesthetic gas (WAG) scavenging system, significant leakage of WAG occurs.

In this incident, a research employee brought an active electrocautery unit near the breathing zone of a rat undergoing inhalational anesthesia. The oxygen-enriched atmosphere created by the WAG emissions promoted a fire, described by affected staff as an “explosion”.


WAG emissions were uncontrolled as a result of using passive scavenging strategies. When an ignition source was brought near the emissions, a fire occurred.

Corrective Actions to Prevent Reoccurrence

An institutional standard requiring active scavenging of WAG during all rodent inhalational anesthesia operations was implemented. 


A Novel Approach to Scavenging Anesthetic Gases in Rodent Surgery. Journal of Occupational and Environmental Hygiene. Volume 10, Issue 9, 2013.