The United States Pipeline and Hazardous Materials Safety Administration (“PHMSA”) responded in a July 12th letter to a Dangerous Goods of America question requesting clarification of the Federal Hazardous Materials Regulations (“HMR”).

The organization requested in an April 7th letter a clarification of the definition of hazardous substance in 49 CFR § 171.8.

The organization asked (paraphrasing):

  • If all hazardous substances listed in the Appendix A to § 172.101 of the HMR must be declared as hazardous materials, or if the hazardous substances are only hazardous materials when packaged in quantities equal to or exceeding the reportable quantity in Appendix A
  • If a hazardous substance that does not meet the definition of any other class or division should be assigned to Class 9 under the entries for UN3082 or UN3077

PHMSA responded in part:

Under § 171.8 a hazardous substance (other than Radionuclides) is defined as the material, including its mixtures and solutions, that:

  1. is listed in the Appendix A to § 172.101 of the HMR;
  2. is in a quantity, in one package, which equals or exceeds its RQ listed in the Appendix A to § 172.101 of the HMR; and
  3. when in a mixture or solution, is in a concentration by weight which equals or exceeds the concentration corresponding to the RQ of the material as shown in the table in § 171.8.

A material must meet all of these requirements in order to be a hazardous substance. A hazardous substance that is not listed by name in the § 172.101 Hazardous Materials Table and is not more appropriately described by another proper shipping name may be assigned to Class 9 under the entries “§ UN 3077, Environmentally hazardous substances, liquid, n.o.s.” and “UN3082, Environmentally hazardous substances, solid, n.o.s.” in accordance with § 173.140(b).

A copy of the letter can be downloaded here.