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 #16-0089R

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

Interpretation Response Details

Response Publish Date:

Company Name: Label Solutions, Inc.

Individual Name: Ms. Tammy King

Location State: MO Country: US

View the Interpretation Document

Response text:

April 1, 2019

Ms. Tammy King
Label Solutions, Inc.
P.O. Box 12
Marshfield, MO  65706

Reference No. 16-0089R

Dear Ms. King:

This letter is further clarification to our October 20, 2016 response (Interp No. 16-0089) to your inquiry requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cylinder labels and Compressed Gas Association (CGA) C-7, Appendix A, A.4.  Specifically, you ask if it is acceptable for the words “flammable gas” or “non-flammable gas”—when placed in the transportation diamond as illustrated in CGA C-7, Appendix A—to be on two lines rather than one line as it appears in § 172.417 of the HMR. 

As we noted in our previous response, the HMR provide several options for labeling of compressed gas cylinders.  Cylinders containing a flammable gas may be labelled with the label prescribed in § 172.417 of the HMR.  Additionally, § 172.400a authorizes a cylinder containing a Division 2.1, 2.2, or 2.3 material to be durably and legibly marked in accordance with CGA C-7, Appendix A.  While neither CGA C-7, Appendix A, nor the HMR specifically illustrate the hazard class text displayed on two lines, § 172.407(f) of the HMR permits the use of labels that conform to the United Nations (UN) Model Regulations in place of a corresponding label that conforms to the HMR.  Section of the UN Model Regulations states that for labels other than Class 7 labels, the insertion of any text (other than the class or division number) in the space below the symbol is authorized provided it relates to the nature of the hazard and precautions to be taken in handling.  As such, a label displaying the words “flammable gas” or “non-flammable gas” whether on one or two lines, that otherwise conforms to the UN Model Regulations is permitted by § 172.407(f) of the HMR.

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


T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

172.417, 172.400a, 172.407(f)


Regulation Sections

Section Subject
172.400a Exceptions from labeling
172.407 Label specifications
172.417 FLAMMABLE GAS label