Common Waste Anesthesia Gas Disposal Deficiencies and How to Fix Them

Before entering the COVID era, one of the hot topics for life safety inspectors was waste anesthesia gas disposal (WAGD).  I cited it many times as a surveyor and know that is a common issue.  So, as we gear back up I am sure it will pick up where it left off.

There are 2 main issues that break down to other issues.

  1. If you have anesthesia in any form there must be a WAGD outlet in that location (NFPA 99

The problem originates during planning.  The architects and engineers that design your facility, do so without knowledge or consideration to the equipment that is later employed.  Most surgery centers are planned and built at the lowest cost possible, so your O.R.’s are equipped with oxygen, vacuum, and maybe medical air.  Then as soon as you place an anesthesia machine in there, now you are required to have a WAGD outlet.  Or maybe you added another procedure to your docket which required anesthesia but your O.R. is not equipped for it.

  1. Improper modification of the system.

Typically this is a result of having an anesthesia machine then making changes so it will connect to the vacuum outlet.  As stated in NFPA 99, each gas outlet/inlet must be identified by a specific color code (O2=green, NO2=blue, Medical Air=yellow).  WAGD is identified by purple, meaning the hose and the outlet wall plate must be identified by purple.  NFPA 99 stated that each connection must be non-interchangeable.  Meaning, it is impossible to attach the O2 outlet hose into the NO2 outlet which eliminates the possibility for human error.

Findings ways around this lead to the improper modification of the system. This comes in many forms, for example:

  • The WAGD hose connected directly to the vacuum inlet, which would require a modification to the connector (sticking a VAC connector at the end of the WAGD hose).
  • Attaching a “Y” device. Where your purple hose and vacuum line are combined, which is then connected to the vacuum outlet.
  • WAGD (purple) hose connected to a vacuum (white) hose which then connects to the vacuum outlet.

I have seen various (and creative) ways of manipulation.  For someone who knows what to look out for, it sticks out like a sore thumb.

My Advice: Take a second to look

Just a quick look will let you know where you stand.  While looking at your anesthesia machine, follow the purple hose from the scavenger (if it is not purple… deficiency) to the purple WAGD outlet.  If there are any devices (“Y” adapters) along the way…deficiency.   If the outlet is not a purple WAGD outlet (or dedicated “EVAC”)…deficiency.

Another indicator is if your doctors are complaining about low suction.  If so, look at the WAGD and vacuum lines to see if they are connected.  This would cut the suction power in about half.  For example, if your vacuum was pulling 100 liters per minute as soon as you attach another line, then that pressure gets divided.  You now have 2 lines pulling at 50 lpm.


If you have questions concerning your waste gas, please feel free to contact me.  We can walk through your system to ensure compliance.  There are options for solving many of the issues found.


Written By: Franklin Sands, Life Safety Compliance Officer

Code References:NFPA 99 (2015) –,,,