Circulation 84,122 • Volume 25, No. 1 • Spring 2010   Issue PDF

An example of yet another medication error – of sorts! Gas Cylinder Colors ARE NOT an FDA Standard!

Gregory Rose, MD; Kristopher Durbin, MD; John Eichhorn, MD

An example of yet another medication error—of sorts!

To the Editor

In a recent submission to the APSF Newsletter, we discussed one application of color coding in anesthesiology practice, specifically how a mislabeled vaporizer was not detected because clinicians relied on the color of the vaporizer and not the label with the name of the anesthetic.1 We recently discovered in our operating rooms an example of the converse, an important component that was properly labeled, but improperly colored.


Figure 1: From left to right, properly colored and labeled oxygen cylinder and nitrous oxide cylinder next to a gray, improperly colored medical air cylinder that should be yellow.

An “E” cylinder fitted to the air yoke of an anesthesia machine was a primer-grey color, not the expected yellow color that indicates medical air in the United States (Fig. 1). There was even a bit of dust on the dome of the tank, indicating that the tank had been on the machine for some time. The cylinder was labeled “Medical Air,” and delivered an FIO2 of 0.21 and no carbon dioxide when analyzed by the gas analyzer on the anesthesia machine. Comparison with an “E” cylinder of carbon dioxide showed the 2 shades of grey were different (Fig. 2).


Figure 2: Two different shades of gray.

It may be a surprise to most practitioners that color coding of medical gas cylinders is not mandatory in the United States. The FDA has only made recommendations in agreement with the Compressed Gas Association (CGA) that “each container is of the proper color to correspond to any color-coding system employed, such as that recommended by the CGA in its pamphlet C-9, Standard Color Marking of Compressed Gas Cylinders Intended for Medical Use in the United States.2 It is up to individual suppliers of medical gas to follow or ignore the tank color guidelines.

In conclusion, we remind our colleagues that color coding of medical gas cylinders is not required by regulation and tank color can be misleading. Gas cylinder content should always be carefully verified by close inspection of the tank label.

Gregory Rose, MD
Kristopher Durbin, MD
John Eichhorn, MD
Lexington, KY


  1. Rose GL, Eichhorn JH, and DiLorenzo A: Implications of a mislabeled vaporizer and the importance of color coding. APSF Newsletter. 2008;23(4):60,66.
  2. Center for Drug Evaluation and Research, Food and Drug Administration. Compressed medical gases guideline. Rockville, Maryland. (Revised) February 1989. Available at:
    .Accessed May 11, 2010.