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.

November 29, 1983

W. H. Phoon, Director
Industrial Health Division
Ministry of Labour Nos. 5 & 7
Halifax Road
Singapore 0922
Republic of Singapore

Dear Dr. Phoon:

This is in reply to your letter of November 10, 1983, addressed to Dr. Ralph E. Yodaiken, Director, Office of Occupational Medicine, Occupational Safety and Health Administration (OSHA), U. S. Department of Labor, requesting information pertaining to work in compressed air and underground tunnelling.

I am enclosing a copy of the OSHA Construction Standards for your reference and use.

In answer to the three specific questions you asked in your letter:

1. The decompression tables used by OSHA can be found on page 151 under 1926.804, Appendix A.

2. A medical lock is required, and this requirement can be found on page 144, 1926.803(b)(9).

3. Requirements for medical examinations and supervision of workers exposed in compressed air atmospheres can be found on page 144, 1926.803(b).

If we can be of further service to you, please call on us.


John B. Miles, Jr., Director
Directorate of Field Operations