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What is the PHMSA/USDOT Definition of a Hazardous Substance?

What is the PHMSA/USDOT Definition of a Hazardous Substance?

The PHMSA/USDOT definition of a hazardous material (HazMat) at 49 CFR 171.8 indicates that the term includes a Hazardous Substance.  In other words, if a material meets the definition of a hazardous substance, then it is also a hazardous material and subject to the regulations of the PHMSA/USDOT when in transportation or offered for transportation.  It is therefore important to understand what, exactly, a hazardous substance is.

Also defined at 49 CFR 171.8, a hazardous substance is a material that meets a certain combination of conditions of chemistry, weight, and concentration.  Hazardous substances, which includes radionuclides, are listed in Appendix A to the Hazardous Materials Table @ 49 CFR 172.101 as follows:

  • Table 1 to Appendix A – Hazardous Substances Other Than Radionuclides
  • Table 2 to Appendix A – Radionuclides

Below, we will review the conditions necessary to designate a material as a hazardous substance.

If a material is in its pure or technical grade, then it is a hazardous substance if both of the following conditions are met:

  •  Its name or representative hazardous waste code (D-code, F-code, or K-code, but not P-codes or U-codes) is listed in Appendix A to the Hazardous Materials Table at 49 CFR 172.101.

and…

  • The weight of the material (lb or kg) is equal to or greater than its Reportable Quantity (RQ) IN ONE PACKAGE.  (The RQ of each hazardous substance is identified in Appendix A to the Hazardous Materials Table @ 49 CFR 172.101).

If a material is in a mixture or solution, then the above two conditions must be true in addition to the following:

  • If a radionuclide, refer to paragraph 7 of Appendix A for further information.
  • If a hazardous substance other than a radionuclide, it must be in a concentration by weight which equals or exceeds the concentration corresponding to the RQ of the material, as shown in Table 1.

Table 1:

RQ Pounds (KG)

Concentration by Weight

Percent

PPM

5,000 (2,270)

10

100,000

1,000 (454)

2

20,000

100 (45.4)

0.2

2,000

10 (4.54)

0.02

200

1 (0.454)

0.002

20

So, when dealing with a mixture or solution it is necessary to know the constituents and their concentrations in order to determine if it is a hazardous substance.

Example:

Acetone has an RQ of 5,000 lbs (2,270 kg) and a corresponding concentration of 10% (100,000 ppm).  A portable tank weighing 7,555 lbs (3,427 kg) contains a mixture of acetone and other petroleum distillates that are not listed in Appendix A to the Hazardous Materials Table.

  • If the concentration by weight of the acetone in the mixture is ≥10% (100,000 ppm), then a reportable quantity of a hazardous substance is present.
  • If the concentration by weight of the acetone in the mixture is <10%, then a reportable quantity of a hazardous substance is not present.

The definition of a hazardous substance specifically excludes the following hazardous materials from the definition of a hazardous substance:

  • Petroleum, including crude oil or any fraction thereof which is not otherwise specifically listed or designated as a hazardous substance in Appendix A to the Hazardous Materials Table (49 CFR 172.101).
  • Natural gas
  • Natural gas liquids
  • Liquefied natural gas
  • Synthetic gas usable for fuel (or mixtures of natural gas and such synthetic gas).

Appendix A to the Hazardous Materials Table is another list you must check prior to transporting or offering for transport a hazardous material.  If it is a hazardous substance, then the Hazardous Material Regulations require you to communicate that information in the form of Markings and on the Shipping Paper.  If the material is not a hazardous substance it may still be a hazardous material subject to the HMR for one or more other reasons.

My HazMat Employee Training will inform you of how to identify a hazardous substance, how to communicate that information when offered for transportation and why it all matters.  Contact me to schedule HazMat Employee or RCRA Training.