OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

October 24, 1988

Mr. B. C. Griffin
GrifTan, Inc.
P.O. Box 760
Pamplico, South Carolina 29583

Dear Mr. Griffin:

This is in response to your letter of July 21, 1988, concerning a "safety cap" designed by you and intended for use on portable DOT compressed gas cylinders. Please excuse the delay in response.

Your specific request was for an interpretation of "special trucks" as identified at 29 CFR 1910.253(b)(5)(ii)(D), copy enclosed The Occupational Safety and Health Administration (OSHA) provides the following:

A "special truck" is a vehicle or cart which provides for stable support of vertical standing DOT portable gas cylinders during movement and at various work locations.

There is provision in the OSHA regulations for the use of a device, such as your safety cap, beyond that required to protect compressed gas cylinder valves as defined by DOT shipping requirements. The movement of compressed gas cylinders with a regulator attached is only permitted while the cylinder is mounted on a special truck. In the workplace, concern is for the protection of the regulator as well as the protection of the cylinder valve. Should a regulator become damaged it is possible for its parts to be ejected with great velocity thereby presenting a significant hazard to workers. For this reason, movement of a compressed gas cylinder with regulator installed may only be accomplished when the cylinder valve and regulator are assured of protection from damage and the cylinder is moved in an erect or nearly erect position on a special truck. Installation of your safety shield does not alter the requirement for a special truck, because the GrifTan Safety Cap does not provide for protection of the regulator.

Use of the GrifTan Safety Cap in place of the DOT one piece safety cap for all situations in which installed caps are required by OSHA regulations is acceptable, if the caps are listed by UL as indicated by your letter. The cap may be used with a regulator installed providing the procedures used assure compliance with the regulations.

If we may be of further assistance, please contact us.


Thomas J. Shepich, Director
Directorate of Compliance Programs


July 21, 1988

Mr. Thomas Shepich
Directorate of Compliance Programs
U.S. Department of Labor - OSHA
200 Constitution Avenue, N. W.
Washington, D. C. 20210

Dear Mr. Shepich:

I have designed a "safety cap" or the protection of the main valve on high pressure cylinders while the regulator is attached and the tank is in use. (A patent was issued July 7, 1987.)

The "GrifTan Safety Cap" is installed on the tank after the transportation cap is removed; the cap opens for access to the valve and installation of the regulator; the cap is then closed and secured with a latch-pin. With the "GrifTan Safety Cap" the valve is protected at all times.

The "GrifTan Safety Cap" is UNDERWRITERS LABORATORIES INC. LISTED and meets Department of Transportation requirements allowing the cap to used as a transportation cap with regulator attached and the valve in the off position.

The "GrifTan Safety Cap" meets OSHA/MSHA standards.

Section 1910.252, Paragraph 2, Code of Regulations 29, Parts 1900 to 1910 reads: "Unless cylinders are secured on a special truck, regulators shall be removed and valve-protection caps, when provided for, shall be put in place before cylinders are removed."

Please provide me with your interpretation of this code and specifically "special truck." Will the "GrifTan Safety Cap' meet OSHA requirements for a valve protection when transporting cylinders with regulators attached and the valve closed?

Thank you for your kind attention to this request.


B. C. Griffin

(For Attachment, see printed copy))