Standard Interpretations - Table of Contents
• Standard Number: 1910; 1910.23(a)(6); 1910.23(c)(1); 1910.27; 1910.132(a); 1910.268

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

May 13, 1986

Mr. Glen N. Felton
Kawanihae Concrete
P.O. Box 4950
Kawanihae, Hawaii 96743

Dear Mr. Felton:

This is in response to your letter of April 21, 1986, in which you request guidance concerning the acceptability of manhole entries through concentric cone or eccentric cone concrete pipe transition sections to underground workplaces.

As you may not be aware, the Occupational Safety and Health Administration (OSHA) does not have standards under which eccentric cones are required. Local jurisdictions may have such requirements.

In Hawaii, the OSHA regulations are enforced by the State of Hawaii through the Hawaii Department of Labor and Industrial Relations:
[830 Punchbowl Street, Suite 321
Honolulu, HI
PH: (808) 586-8844]
You may also wish to contact them.

In the private sector, OSHA standards and regulations specify the safe proce