Compressed gas cylinders transported in underground tunnels

May 5, 1992

Mr. George Brown, P.E. Director,
Corporate Safety/Risk Management
Obayashi Corporation
[Recipient address omitted]
Dear Mr. Brown:

This is in response to your January 30 letter requesting an interpretation of Occupational Safety and Health Administration (OSHA) requirements addressing the transportation of compressed gas cylinders. I apologize for the delay in responding to you.

As you know, the present interpretation of paragraphs 1926.350(a)(4) and (9) prohibits the transporting of compressed gas cylinders in the horizontal position by powered vehicle at construction sites. However, considering the unique hazards associated with underground transportation of gas cylinders, your proposed method of securing and storing the cylinders while transported underground, and that current Department of Transportation regulations allow this practice under limited conditions, OSHA would consider your described method of transporting compressed gas cylinders as a de minimis situation at your San Pedro Creek and San Antonio River tunnel and shaft project in San Antonio, Texas if conducted under the following conditions:

1. Oxygen cylinders are secured against movement in all directions in a rack secured to the segment car.

2. Acetylene cylinders are secured against movement in all directions in a rack secured to the segment car. The tops of all acetylene cylinders are elevated so that the cylinders are inclined at an angle of not less than 30 degrees from horizontal (to protect against loss of acetone).

If we can be of any further assistance please contact Mr. Roy F. Gurnham or Mr. Dale Cavanaugh of my staff in the Office of Construction and Maritime Compliance Assistance at (202) 523-8136.

Sincerely,
Patricia K. Clark, Director
Directorate of Compliance Programs

[Two requester letters reproduced on OSHA page; omitted here.]