Calculating RQ for Hazmat Mixtures and Solutions

In a recent blog, we discussed shippers’ responsibilities for offering a reportable quantity (RQ) of a hazardous substance for transportation.

To recap, not all DOT hazardous materials are hazardous substances. DOT lists hazardous substances in Appendix A to the 172.101 Hazmat Table. When shipping a single hazardous substance, identifying the RQ and ensuring compliance is relatively straightforward.

But what if you ship a mixture or solution?

In order for a mixture or solution to be regulated as a hazardous substance, two things must be true. A mixture or solution is regulated as a hazardous substance only when it is: 

• In a quantity, in one package, which equals or exceeds the reportable quantity (RQ) listed in the appendix A to § 172.101, AND
• In a concentration by weight which equals or exceeds the concentration corresponding to the RQ of the material, as shown in the table found in 49 CFR 171.8, as part of DOT’s definition of hazardous substance.

The RQ concentration table provides a concentration percentage by weight for each RQ assigned to a substance in 172.101 Appendix A—5,000 lbs., 1,000 lbs., 100 lbs., 10 lbs. and 1 lbs.
 
Example
Say you have a mixture that contains benzene. Benzene is a hazardous substance with a reportable quantity of 10 pounds, according to the 172.101 Table, Appendix A.

When we consult the concentration chart, we see that a substance with a 10-pound RQ must also make up 0.02% (or 200 parts-per-million) or more of a mixture or solution in order to be regulated as a hazardous substance.

Therefore, if your mixture or solution contains 0.02% or more of benzene (by weight) AND that represents at least 10 lbs. of benzene, you must mark RQ on the shipping papers and on a non-bulk package.

When is a mixture or solution that contains a hazardous substance regulated as a hazardous substance?

• If it meets the percentage AND meets or exceeds the RQ quantity, it is regulated as a hazardous substance.
• If it meets the percentage, but not the RQ, it is not regulated as a hazardous substance
• If it meets the RQ, but not the percentage, it is not regulated as a hazardous substance