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.

December 10, 1984

Mr. Haggai Cohen
Acting Director, Safety Division
National Aeronautics and
Space Administration
Washington, D.C. 20546

Dear Mr. Cohen:

This is in response to your October 25 letter requesting general comments on the hydrogen safety manual in time for your Review Committee meeting on December 11 and 12. Because of the time constraints our review was limited to the manual's general organizational structure and obvious conflicts with OSHA's standards.

Our preliminary comments were provided by the Directors of Health Standards and Safety Standards and are as follows:

1. Control measures not required by OSHA but included in the document are: certification of operators, use of a two-barrier safety feature (at least two simultaneous mishaps must occur before an incident/accident takes place), and maintaining negative pressure (relative to communication rooms) for uncontained systems.

2. It is suggested that the manual list cross references from OSHA's regulations to other regulations, e.g., 29 CFR 1910.103(b)(1)(iii) should be cross referenced to ANSI B31.1-1967 and B31.1-1969 addenda.

3. "Should" is used instead of "shall". Examples are paragraphs 3.3.2.a.4, 3.3.2.b.1, and 3.3.4.d (first should).

4. Section 1910.103 contains specific provisions on vaporizers; we were unable to locate similar language in the manual.

5. 29 CFR Part 1910 is listed in Appendix C, Transportation Codes; OSHA's standard is not a transportation standard and this should be clearly indicated.

We hope these general comments will be helpful.

We will try to have comments of both a technical and general nature completed and transmitted to you by the January 18, 1985, date that you requested in your letter.


John B. Miles, Jr.
Directorate of Field Operations

October 25, 1984

Assistant Secretary of Labor
for Occupational Safety and Health
Rm S-2315
200 Constitution Avenue, NW
Washington, DC 20210

Subject: NASA Supplementary Standard for Hydrogen Safety

The National Aeronautics and Space Administration (NASA) is undertaking a contractual effort to develop a hydrogen safety manual and an oxygen safety manual. An internal NASA committee has been established to manage these efforts and they will meet on December 3, 1984, to review and discuss the draft hydrogen safety manual prior to its being distributed within NASA for general review by both management and employees and their representatives in CY 85.

In accordance with 29 CFR 1960.18, the enclosed draft of the "Hydrogen Safety Manual" is provided for Department of Labor review for consistency with other OSHA standards. Since the review committee desires to obtain feedback from the Department of Labor prior to the December 3 meeting, comments are requested by November 30, 1984. Questions may be directed to Mr. Wayne Frazier (202)453-2392 in the Safety Division.

Haggai Cohen
Acting Director, Safety Division
National Aeronautics and Space
Washington, D.C. 20546