The United States Pipeline and Hazardous Materials Safety Administration (“PHMSA”) addressed in a May 5th letter whether the contents of an emptied oxygen cylinder are hazardous materials subject to the federal Hazardous Materials Regulations (“HMR”).

The question had been posed to PHMSA by GBLTSC Inc. an ENCISO Industries Co. in a November 20, 2015 email.

PHMSA concludes that the contents of an emptied oxygen cylinder are not a hazardous material subject to the Hazardous Materials Regulations.

The federal agency notes in part:

                     In accordance with § 173.115(b), a Division 2.2 gas is a non-flammable, non-poisonous compressed gas that includes compressed gas, liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant gas, and oxidizing gas (emphasis added). Therefore, the contents of a non-pressurized cylinder (a cylinder that exerts a gauged pressure of less than 200 kPa at 20 °C) that previously contained a Division 2.2 gas, including one with an oxidizer subsidiary hazard, no longer meets the definition of a Division 2.2 gas and is not subject to the requirements of the HMR. However, if a cylinder is marked to represent that it has been manufactured to a DOT specification or UN standard in Part 178, it is still subject to all applicable requirements of Part 178 and continuing qualification and maintenance requirements of Part 180.

Click here to download a copy of the letter.