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.

July 26, 1990

Mr. Jerry Shreter Baytank (Houston) Inc. 12211 Port Road Seabrook, Texas 77586

Dear Mr. Shreter:

This is in response to your letter of May 18, and in response to your telephone conversation with a member of my staff on June 13, in which you sought the Occupational Safety and Health Administration's (OSHA) written confirmation that your company may base its design of a 9'0" high dike wall that will surround the planned construction of two 88 ft. spheres for the storage of propylene, a liquefied petroleum gas (LPG), on the latest edition of the National Fire Protection Association's (NFPA) 30, Flammable and Combustible Liquids Code Handbook.

We have reviewed your request and concluded that 29 CFR 1910.106 (Flammable and Combustible Liquids) does not apply to the handling and storage of LPG. The provisions for storage and handling of LPG in the OSHA regulations are found at 1910.110 (Storage and handling of liquefied petroleum gases); however, .110 does not apply to marine terminal facilities. Similarly, NFPA 30 and 58, OSHA's sources for its .106 and .110 standards, respectively, do not apply to marine terminal facilities. Section 1-2.3.1(b) of NFPA 58, 1986 Edition, recommends that American Petroleum Institute (API) Standard 2510-1978 (API 2510-1989 is the latest Edition) Section 3.2.5, be applied to marine terminals and other listed facilities. Copies of pertinent sections of the referenced standards are attached for your information.

The standards adopted by OSHA in 29 CFR Part 1910 are minimum requirements. The standards do not address requirements for all types of industries and operations. In instances where a particular condition is not covered by a specific OSHA standard, employers are obligated, under the general duty clause (Section 5(a)(1) of the Occupational Safety and Health Act (OSH Act), to provide a place of employment free of recognized hazards which may cause death or serious physical harm.

OSHA uses various references, generally including the API standards, to evaluate industry practice as a part of the justification for issuance of general duty clause citations. Section 3.2.5 of API Standard 2510 specifically limits the height of dikes or walls to 6 feet, except on sloping terrain, in order to provide safe access to and egress from the storage facility. Any deviation from the standard, for instance, your company's erection of a 9'0" high dike wall, could result in violation of Section 5(a)(1) of the OSH Act subsequent to an OSHA inspection.

In conclusion, OSHA does not have regulations governing the design and the erection of dike wall heights surrounding LPG storage area at marine terminal facilities. The standards applicable to this situation are found at API Standard 2510. I hope the information provided will be of assistance to you. If you have additional questions about this matter, please feel free to contact James C. Dillard, of my staff, at (202) 523-8041.


Patricia K. Clark Director Designate Directorate of Compliance Program