December 10, 2003

Mr. Harry Lancaster
Health and Safety Specialist
Duke/Fluor Daniel
PO Box 1011
Charlotte, NC 28201

Dear Mr. Lancaster:

Thank you for your October 28, 2002 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs. We apologize for the delay in providing a full response. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any questions not delineated within your original correspondence. You had specific questions regarding the application of 29 CFR 1910.24(b) to secondary containment structures surrounding bulk chemical storage tanks. Your paraphrased inquiry and our response follow.

Inquiry: Are fixed industrial stairs required to provide access to secondary containment structures surrounding bulk chemical storage? It is common industry practice to provide fixed ladders for access to these areas because:

1. Access to the secondary containment structures is not routinely required (i.e., not daily or at the end of each shift);
2. All connections and equipment for routine operation of these tanks are located outside the secondary containment structures; and
3. Entry into secondary containment structures would not involve employee exposure to acids, caustics, gases, or other harmful substances under normal conditions. Employee exposure to acids, caustics, gases, or other harmful substances would occur only in the event of an uncontrolled release, which would be managed as prescribed under 29 CFR 1910.120(q).

Response: If none of the conditions of 29 CFR 1910.24(b) that would trigger the use of fixed industrial stairs are met, then it would be appropriate to use fixed ladders that meet the requirements of 29 CFR 1910.27. To reiterate the requirements of 29 CFR 1910.24(b), fixed industrial stairs shall be provided for access from one structure level to another:

1. Where operations necessitate regular travel between levels, and for access to operating platforms at any equipment which requires attention routinely during operations;
2. Where access to elevations is daily or at each shift for such purposes as gauging, inspection, regular maintenance, etc.;
3. Where such work may expose employees to acids, caustics, gases, or other harmful substances; or
4. Where for such work the carrying of tools or equipment by hand is normally required.

Each secondary containment structure and the location and frequency of associated work activities would need to be evaluated on a case-by-case basis to determine if any of the conditions of 29 CFR 1910.24(b) are met. If any one of the above conditions are met, then fixed industrial stairs would be required. Although not specifically addressed in this response, other OSHA standards such as those concerning flammable and combustible liquids and permit-required confined spaces may be also be applicable to diked areas.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. 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 http://www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at 202-693-1850.

Sincerely,

Directorate of Enforcement Programs