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 16, 1977

Mr. Dewey Bowers
Director of Safety
1706 Olive Street
Saint Louis, Missouri 63103

Dear Mr. Bowers:

This is in response to your letter dated October 14, 1977 concerning positive identification of persons working underground in tunnels and shafts, caissons, cofferdams, and compressed air tunnels. We were pleased to meet with you on October 6, 1977 in order to discuss these matters.

The identification system utilized in your shaft and tunnel work, when properly implemented and controlled, would appear to provide positive identification of employees underground and during shaft and tunnel work. The method of maintaining an accurate record and location of employees by using identification check-in/check-out board placed at the tunnel shaft would be also appear to meet the intent of [29 CFR 1926.800(c)].

As you indicated, the subject standard does not necessarily require an employee at the check-in and check-out location during the time employees are underground. However, your attempt to standardize your procedures in regard to the subject standard may not be completely successful because of the specific unique problems encountered in tunneling.

I would also bring to your attention that if work is being conducted in compressed air tunnels, the additional requirements of [29 CFR 1926.803] must be met.

Thank you for your concern and continued interest in safety and health. If I may be of any further assistance, please feel free to contact me.


John K. Barto, Chief
Division of Occupational Safety Programming

[Corrected 05/28/2004]