{"operation":"document","citation":"98-0347","title":"Ms. Denise M. Oas — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2000-01-05","effective_on":null,"summary":"98-0347 concerning 173.33.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-98-0347.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-98-0347.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-98-0347","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/1998/980347.pdf","body":"<<<PAGE 1>>>\n\nUS. Department\nof Transportation\nWashingion, DC. 0590\nResearch and\nWashington, D.C.\nspecial Programs\nAdministration\nJAN 5 2000\nMs. Denise M. Oas\nP.O. Box 7377\nReference. No. 98-0347\nNorth Kansas City, MO 64116\nDear Ms. Oas:\nThis is in response to your letter concerning a provision in 49 CFR 173.33(a)(2). This\nprovision restricts a person from loading or accepting different materials on the same\nmulti-unit cargo tank motor vehicle if, as a result of any mixture of the materials, an\nunsate condition would occur such as an explosion, fire, excessive increase in pressure or\ninconvenience it may have caused.\nheat, or the release of toxic vapors. I apologize for the delay in responding and regret any\nIn your letter, you referred to a statement published in the June 17, 1991 Federal Register\npublication in which we stated that the restriction in § 173.33(a)(2) was not intended to\nprevent ine shipment of materals that, if mixed, would produce a moderate exothermic\nreaction that would not start a fire, rupture the tank or release acutely toxic vapors. You\nasked if this interpretation is correct and if, not, just how much of an increase in pressure\nor heat is permitted before creating a violation of this section.\nThe above interpretation is correct. In addition to meeting the provision in\n§ 173.33(a)(2), cargo tanks must meet the general requirements for all bulk packagings in\nlimited, and closed, so that under conditions that normally occur in transportation: 1)\nthere will be no identifiable release of hazardous materials to the environment; 2) the\neffectiveness of the packaging will not be substantially reduced; and 3) there will be no\nmixture of gases or vapors in the package which could through any credible spontaneous\nMany factors affect how materials may react with each other. They include the chemical\ncomposition and properties of the materials involved, and how they react to air, water,\ncontaminants, or temperature conditions during transportation. Because there are so\nmany variables, under the Hazardous Materials Regulations, the parties involved must\nevaluate the potential risk posed by different materials that are offered and accepted for\ntransportation on the same multi-tank cargo tank motor vehicle. If your client has\n173.33\n980347\n\n<<<PAGE 2>>>\n\n-\nspecific questions on making these determination, your client may contact Mr. Charles\nHochman, Office of Hazardous Materials Technology, at (202) 366-4545 for assistance.\nI hope this satisfies your request.\nSincerely,\nitatte 2. Michell\nHattie L. Mitchell, Chief\nRegulatory Review and Reinvention\nOffice of Hazardous Materials Standards\n\n<<<PAGE 3>>>\n\n98-0347\nDENISE M. OAS\nP.O. BOX 7377\nmack\nNORTH KANSAS CITY. MISSOURI 64116\n$173.33\n(816) 455-7300\nNovember 12, 1998\nMr. Edward T. Mazzullo - DHM -10\nDirector, Office of Hazardous\nMaterials Standards, RSPA\n400 Seventh Street, Southwest\nU.S. Department of Transportation\nRoom 8100\nWashington, DC 20590\nDear Mr. Mazzullo,\nA client of mine has asked for an interpretation from your office regarding 49\nC.F.R. 173.33(a)(2) which provides that:\nTwo or more materials may not be loaded or accepted for\nray sportatio it t matemes, ago tank motor tich ve if occur, suh as\nnv mixture ot the material:\nan explosion, fire, excessive increase in pressure or heat, or the release\nof toxic vapors.\nA statement published in the Federal Register in 1991 noted that the intent of the\nsection is to prevent shipment of materials that, if mixed, would cause a fire, a tank\nrupture or the release of acutely toxic vapors. 56 Fed. Reg. 27872 June 17, 1991). It\nfurther noted that the section was not intended to prevent the shipment of\nmaterials that, if mixed, would produce a moderate exothermic reaction that would\nnot start a fire, rupture the tank or release acutely toxic vapors.\npressure or heat that is prohibited is an increase sufficient to cause a fire, tank\nThank you for your assistance.\nVery Truly Yours,\nDeni Eas\nDeni Oas","truncated":false,"body_characters":3971}