Classification of BHMT Amine Blend
Pipeline and Hazardous Materials Safety Administration · May 30, 1997 · Reference No. 97-0145
Interprets: 49 CFR § 172.101
Reggie’s quick take
A company asked whether one shipping description could cover all shipments of its BHMT amine blend, even though some batches are liquids and others are solids. The agency said no. Solids and liquids must each be described as what they are, under § 171.8 and § 172.101. The agency also said the shipper must classify the material, and offered its opinion that this material should be described as Amines, liquid, corrosive, n.o.s., 8, UN 2735, PG II. On the melting-point question, the agency said a material's physical form when packaged or loaded for transport decides whether it counts as a solid or a liquid.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your letter regarding your material identified as BHMT amine blend (BAB). I apologize for the delay in responding and hope it has not caused any inconvenience.
Your questions have been paraphrased and answered as follows:
Q1. Is it acceptable to use one proper shipping description to describe all shipments of BAB regardless if some meet the definition for a liquid, and others meet the definition for a solid?
A1. The answer is no. It is not acceptable because solids must be identified as solids and liquids must be identified as liquids according to the definitions provided in § 171.8 of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) and § 172.101.
Q2. Which proper shipping name is appropriate to apply to shipments of BAB?
A2. As provided in § 173.22, it is the shipper's responsibility to classify properly a hazardous material. This office does not perform that function. If a material is not specifically listed by name in the Hazardous Materials Table (§ 172.101), then selection of a proper shipping name must be made from the general description entries corresponding to the specific hazard class, packing group, and subsidiary hazards of the material. However, based on the information you provided, it is the opinion of this office that the material should be described as Amines, liquid, corrosive, n.o.s. (list 2 major components), 8, UN 2735, PG II.
Q3. Can DOT provide guidance on classifying materials as a liquid or solid when the materials are known to exhibit multiple melting points over a range @ that includes the 20°C threshold value?
A3. The physical form of a material when packaged-dud loaded for transportation determines whether it is either a solid or a liquid.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.