# Mr. Scott C. Morrison — Hazardous Materials Safety Interpretation **Citation:** 03-0044 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2003-06-06 03-0044 concerning 173.33. ## Document text <<>> of Transportatior J.S. Department 400 Seventh St., S.W. Washington, D.C. 20590 JUN -6 2003 Mr. Scott C. Morrison 2009 South Trillium Drive Reference No. 03-0044 Aliquippa, PA 15001 Dear Mr. Morrison: This in response to your letter concerning the requirement in paragraph 7.c. (4) of Exemption DOT-E-11537 that prohibits offerors and carriers from loading on the same motor vehicle intermediate bulk containers (IBCs) containing different hazardous materials that, if mixed, would cause an unsafe condition to occur. You asked if the reason for segregating these materials is essentially the same as that prescribed in 49 CFR 173.33(a)(2) and discussed in letter Reference No. 98-0347. The answer is yes. The Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) contain various requirements covering the loading of hazardous materials that would react dangerously with each other and cause an unsafe condition to occur. For example, see §§ 173.21(e) and parties involved must evaluate the potential risks posed by different materials that are loaded on 173.33(a)(2). As we stated in the referenced letter, because there are so many variables, the the same motor vehicle. Sincerely, Hothe z. mitthell Hattie L. Mitchell, Chief Regulatory Review & Reinvention Office of Hazardous Materials Standards 173.33 030044 <<>> Edmonson 2009 S. Trillium Dr. Scott C. Morrison $|73,33 Aliquippa, PA 15001 (724) 375-6138 February 4, 2003 Cargo Tanks Mr. Edward T. Mazzullo 03-0044 Director, Office of Hazardous Materials Standards 400 7th Street S.W U.S. DOT/RSPA (DHM-10) Washington, D.C. 20590-0001 RE: Exemption DOT E-11537 Interpretation Letter on 173.33(a)(2) to Denise E. Oas issued on 01/05/2000 Reference No. 98-0347 Dear Mr. Mazzullo: This letter is to follow up my telephone conversation with Eileen at the Hazardous Material Information Center on 2/3/03 to request clarification of Item 7.c.(4) in DOT E-11537 (on discharge from IBC's without removal from the vehicle which states: "Two or more materials may not be loaded on the same vehicle if, as a result of any mixture of the materials, an unsafe condition could occur." While doing research on this exemption, I came across Interpretation Letter 98-0347 that concerns the loading of material on the same multi-unit cargo tank. The wording in paragraph 1 of this letter and 49 CFR 173,33(a)(2) seems to be similar to the wording in the DOT E-11537: "...This provision restricts a person form loading or accepting different materials on the same multi-unit cargo tank motor vehicle if, as a result of any mixture of the materials, (E added the emphasis to the wording in bold). an unsafe condition would occur such as an explosion.. My question is whether the advice in Letter 98-0347 would also be applicable to Item 7.c. (4) of the DOT E-115377 Specifically, the advice in paragraph 4 which states: "Many factors affect how materials may react with each other...Because there are so many variables, under the Hazardous Materials Regulations, the parties involved must evaluate the potential risk posed by different materials that are offered and accepted for transportation. Thank you for your assistance in this matter. Sincerely, Fat Movinon Scott C. Morrison ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `3a9a4d6dc195cc4029defff8fe7a8902050a9a48d49bb8b267a4ac94a712e8b0` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-23T17:25:20.299Z - Document slug: `phmsa-interpretation-03-0044` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [], "individuals": [ "Mr. Scott C. 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