Acetone cyanohydrin, stabilized
Pipeline and Hazardous Materials Safety Administration · Jul 11, 2007 · Reference No. 07-0101
Reggie’s quick take
A shipper asked PHMSA whether a material it ships, a nitrile with a dermal toxicity of 17 mg/kg, should be described as "Acetone cyanohydrin, stabilized" or under a different name. An earlier PHMSA letter had said that name did not fit because the material is not an inhalation hazard, and had recommended "Toxic liquid, organic, n.o.s." This time PHMSA said the shipper must classify and describe its own material, but gave its opinion that "Nitriles toxic liquid, n.o.s., 6.1, PG I" (UN 3276) is the more appropriate proper shipping description, based on the data and new details the shipper provided.
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 May 9, 2007 letter regarding the applicability of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) to the transportation of acetone cyanohydrin. Specifically, you request clarification of a previous letter of interpretation issued to you by this office on March 16, 2007 (Ref No.: 07-0046), which stated that the proper shipping name "Acetone cyanohydrin, stabilized" is not an appropriate proper shipping name for your material because the material does not meet the definition of an inhalation hazard. Based on the information you provided at that time, we recommended using the generic proper shipping name, "Toxic liquid, organic, n.o.s." In your follow-up request for interpretation you have added that the material is a nitrile with a dermal toxicity of 17 mg/kg. Based on the additional information, you ask if it is more appropriate to use the proper shipping description "UN 3276, Nitriles Toxic Liquid, n.o.s., 6.1, PG I."
As you are aware, it is the shipper's responsibility to properly class and describe a hazardous material. This office does not perform that function. However, based on the technical data you originally submitted and the additional information you provided in this follow-up letter, it is the opinion of this office that "Nitriles toxic liquid, n.o.s., 6.1, PG I" is a more appropriate proper shipping description for your material.
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.