Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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 procedures and acceptable practices for entry through manholes and vertical transition sections of underground workplaces. The safety of working conditions at completed and in-operation facilities are regulated under 29 CFR 1910, the General Industry standard.

OSHA has no prohibition regarding employee entry into concentric cone sections. However, installers of new vertical transition sections should preferentially consider eccentric cones due to the greatly improved egress along a vertical fixed ladder rather than the problem of descending and ascending an inverted canted ladder of the type installed in concentric cone transition sections.

OSHA requires that employees exposed to fall hazards be safeguarded. Where applicable, the following standards and OSHA Instructions (enclosed) pertain to the safeguarding of employees who egress through manholes:

  1. 29 CFR 1910.23(a)(6) and 1910.23(c)(1).
  2. 29 CFR 1910.27.
  3. 29 CFR 1910.132(a).
  4. OSHA Instruction STD 1-1.9, December 29, 1978.
  5. OSHA Instruction STD 1-1.13, April 16, 1984.

Although it seems that there may be a relationship between the lack of compliance with OSHA standards and product liability, compliance with OSHA standards may provide no relief from liability. We suggest you discuss your concern with an attorney.

Should we be of further assistance, please contact me.



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

[Corrected 3/24/2009]