USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #22-0041

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Pilot Chemical Company

Individual Name: Megan O’Connor

Location State: OH Country: US

View the Interpretation Document

Response text:

September 9, 2022

Megan O'Connor
Pilot Chemical Company
9075 Centre Pointe Dr., Suite 400
West Chester, OH  45069

Reference No. 22-0041

Dear Ms. O'Connor:

This letter is in response to your April 22, 2022, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to classification and selection of a proper shipping description for a liquid hazardous material. You state that the hazardous material meets the criteria for Class 8 (Packing Group (PG) II), Class 3 (PG III), and Division 6.1 (PG III), which—according to the precedence of hazard table in § 173.2a—would make the corrosivity hazard the primary hazard. However, you state that you are having difficulty finding an appropriate hazardous materials description in the § 172.101 Hazardous Materials Table (HMT) for this material, consistent with the precedence of hazard table in § 173.2a. You note the proper shipping description "UN3286, Flammable liquid, toxic, corrosive, n.o.s., 3, (6.1, 8), PG II," which reflects all three hazards posed by the material, and inquire whether it is appropriate to use this description, or whether using another description, such as "UN2920, Corrosive liquids, flammable, n.o.s., 8, (3), PG II," is more appropriate, even though it does not reflect the subsidiary toxicity hazard.

It is the shipper's responsibility to properly classify and describe a material. However, it is the opinion of this Office that using UN2920 is more appropriate because it corresponds to corrosivity being the primary hazard of the material. As provided in § 173.2a, the Class 8 liquid (PG II) hazard takes precedence over the Class 3 (PG III) and Class 6.1 (PG III) hazards. Note that, while not required, additional information regarding subsidiary hazards posed by materials (e.g., oral toxicity) in transport may be included on a shipping paper, in addition to the basic description. In accordance with § 172.202(a)(3), the subsidiary hazard class or division number is not required to be entered when a corresponding subsidiary hazard label is not required. Section 172.101(g) instructs that § 172.402 may require that a label other than that specified in Column (6) of the HMT be affixed to a package, in addition to what is specified in Column (6). Section 172.402(a)(2) instructs that if not already labeled according to Column (6) of the HMT, a package shall be labeled with subsidiary hazard labels, in accordance with the subsidiary hazard label table, which requires a label for 6.1 (PG III) toxicity hazard.

Thus, depending on the quantity of material shipped, if labeling is required, then the hazardous materials description on the shipping paper should also include the 6.1 hazard.

I hope this information is helpful. Please contact us if we can be of further assistance.


Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

172.101, 172.101(g), 172.402, 172.402(a)(2), 173.2a

Regulation Sections

Section Subject
172.101 Purpose and use of hazardous materials table
172.402 Additional labeling requirements
173.2 Hazardous materials classes and index to hazard class definitions