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 #13-0111 ([Baker Hughes] [Mr. Aubrey R. Campbell])

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

Interpretation Response Details

Response Publish Date:

Company Name: Baker Hughes

Individual Name: Mr. Aubrey R. Campbell

Location State: TX Country: US

View the Interpretation Document

Response text:

July 31, 2013


Mr. Aubrey R. Campbell
Baker Hughes
2001 Rankin Road
Houston, TX 77073

Ref No.: 13-0111

Dear Mr. Campbell:

This is a response to your May 17, 2013 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 100-185) with regard to the segregation of hazardous materials by highway.  Specifically, you seek clarification on the segregation requirements applicable to materials of the same hazard class in the same transport vehicle.  

In your incoming letter you state that your company offers for transportation “UN1908, Chlorite Solution, Class 8, Packing Group (PG) II;” “UN1791, Hypochlorite Solutions, Class 8, PG III;” and “UN1789, Hydrochloric Acid Solution, Class 8, PG II” in separate intermediate bulk containers (IBCs).  You correctly note that since these materials share the same hazard class, with no subsidiary hazards, there are no segregation restrictions for motor vehicle transport in accordance with the segregation table in § 177.848(d).  However, you provided data that indicates that the event of commingling, these materials would create Chlorine Dioxide gas.  “Chlorine Dioxide (not hydrate)” is forbidden for transportation per the Hazardous Materials Table (HMT; § 172.101).  You question the applicability of § 173.21(e) in this situation, which prohibits the transportation of materials in the same packaging, freight container, or overpack, the mixing of which would cause a dangerous evolution of poisonous gases or vapors.

Based on the classification of these materials, the segregation table found in § 177.848(d) does not explicitly prohibit these products from being transported on the same vehicle by highway.  However, as specified in § 173.21(e), it is forbidden to offer for transportation or transport “[a] material in the same packaging, freight container, or overpack with another material, the mixing of which is likely to cause a dangerous evolution of heat, or flammable or poisonous gases or vapors, or to produce corrosive materials.”  Regardless of the segregation requirements in § 177.848, if the hazardous materials offered or transported will dangerously react when placed together in the same packaging, freight container or overpack they are forbidden.  However, a transport vehicle does not meet the definition of a packaging, freight container or overpack and therefore § 173.21(e) does not forbid the offering for transportation or transport of these materials in same transport vehicle.

We recognize the concerns that you have regarding the transport of Chlorite and Hypochlorite Solutions with Hydrochloric Acid in the same transport vehicle.  However, we believe that the packaging requirements for these materials mitigates the potential for comingling and subsequent dangerous evolution of gas.  If you believe that the current requirements in § 173.21(e), should be extended to include transport vehicles, you may submit a petition to amend the HMR in accordance with the procedures set forth in 49 CFR Part 106.

I hope this information is helpful.  If you have any more questions, please do not hesitate to contact this office.


Robert Benedict
Chief, Standards Development
Standards and Rulemaking Division

177.848(d), 173.21

Regulation Sections

Section Subject
173.21 Forbidden materials and packages
177.848 Segregation of hazardous materials