By Andy Altemos, Senior Technical Advisor    November, 2007

While progress has been made over the last twenty years in harmonizing DOT/HMR International transportation there remains disharmony in the DOT classification of “Combustible Liquids” hazard class. In this article Mr. Altemos discusses the three distinct categories of combustible liquids; Non-Bulk, Bulk, and Bulk for Liquids With Flashpoints above 140ºF to 200ºF, and the impact the DOT provisions have on both Shippers and Transporters of Combustible Liquids. PHMSA has initiated a review of these regulations, but until there is a resolution there will continue to be compliance issues for the transportation of these materials.

Very significant progress has been made over the last 20 years in harmonizing the DOT Hazardous Materials Regulations (HMR) with international transport regulations modeled after the UN Recommendations on the Transport of Dangerous Goods (“the UN Model Regulations”) - for example the IMO’s IMDG Code and the ICAO Technical Instructions (as well as the associated IATA DGR). However, one area where considerable disharmony remains is in relation to the DOT “Combustible liquids” hazard class. This disharmony poses serious obstacles and problems for the international transport of these materials.

As readers recognize, under the UN Model Regulations and associated international regulations, the upper limit for regulation of liquids as Class 3 “flammable liquids” is a closed cup flashpoint of 60°C (140°F). The same is generally true under the HMR as far as “flammable liquids” are concerned. However, in addition, the HMR also regulate, with certain exceptions, liquids with a closed cup flashpoint of up to (but not including) 93°C (200°F) as “combustible liquids”.

In addition, other than for transportation by vessel and aircraft, § 173.150(f)(1) of the HMR permits certain flammable liquids (i.e., liquids with a flashpoint of not more than 60°C (140°F)) that have a flashpoint at or above 38°C (100°F), to be reclassified as combustible liquids. So reclassified, when in a non-bulk packaging § 173.150(f)(2) makes the material eligible for exception from regulation unless the combustible liquid is a hazardous substance, a hazardous waste, or a marine pollutant. Finally, with regard to international transport, while the HMR generally authorize the use of the relevant international regulations - such as the IMDG Code and ICAO Technical Instructions for shipments moving by vessel and aircraft, respectively § 171.22(c) provides that when a material is regulated under the HMR but not regulated under the applicable international regulation, the material concerned must be transported in accordance with all applicable requirements of the HMR. A prime example of such a class of materials is, of course, combustible liquids.

Considering these provisions of the domestic and international regulations, what issues, problems, and potential pitfalls then, face those who transport in international commerce, materials considered “combustible liquids” under the HMR? It is probably easiest to review the situation by looking separately at three distinct “categories” of combustible liquids.

1. Non-bulk
The first category consists of liquids with flashpoints at or above 38°C (100°F) but not more than 60°C (140°F), packaged in non-bulk packagings. For transport by motor vehicle and rail, DOT provides that these flammable liquids can be reclassified as “combustible liquids”. They then may be considered excepted from regulation - but for transport by vessel and aircraft when they must be classified and transported as Class 3 materials. The potential pitfalls with this category of combustible liquid do not arise from an out-and-out inconsistency between the HMR and the international regulations. Rather, the risk here arises when materials moved domestically under this exception by motor vehicle or rail as non-hazardous are subsequently and inadvertently transported by vessel or aircraft without being recognized as the Class 3 flammable liquids that they actually are. This does occur with some frequency. Notwithstanding the potential for such oversight, this exception for combustible liquids in non-bulk packagings is of important and significant benefit to many industries that ship these materials within the United States by motor vehicle or rail. Resolution of the issues associated with this category of combustible liquids may lie more in better training and awareness, than in some kind of modification to the regulations themselves.

2. Bulk.
The next category of combustible liquids offered for consideration again consists of liquids with flashpoints at or above 38EC (100EF) but not more than 60EC (140EF), but packaged in bulk packagings. Again, for transport by motor vehicle and rail, DOT permits these flammable liquids to be reclassified as “combustible liquids”. While not eligible for a complete exception from regulation as are similar liquids in non-bulk packagings, these materials are nevertheless offered very significant exceptions from regulation under § 173.150(f)(3). Indeed, this category of combustible liquid is subject only to the specific requirements of the HMR as listed in that paragraph. A number of requirements of the HMR that would be applicable to these materials if they were classified as “flammable liquids” are not applicable. These include, but are not limited to, requirements concerning the use of...

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