Billing Code - PHMSA - Department of Transportation

materials designated as hazardous materials. Paragraph (c)(10) of § 172.101 prescribes
how mixtures or solutions not identified specifically by name are described.
PHMSA is revising § 172.101(c)(10) to incorporate language adopted in the 17 th
Revised Edition of the UN Model Regulations that states mixtures and solutions must meet
the definition of one or more hazard classes to be classified as a hazardous material. This
change will clarify that for a mixture or solution composed of one or more components that
are classified as a hazardous material, the resulting mixture or solution must meet the
definition of one or more hazard classes to be classified as a hazardous material.
Paragraph (k) of § 172.101explains the purpose of column (10) of the HMT and
prescribes the vessel stowage and segregation requirements for specific entries in the
HMT. Column (10) is divided into two columns: column (10A) [Vessel stowage] specifies
the authorized stowage locations on board cargo and passenger vessels and column (10B)
[Other provisions] specifies special stowage and segregation provisions.
We are modifying these instructions by revising the vessel stowage location
requirements for explosives and reducing the number of explosive stowage categories from
15 to 5. Specifically, the explosive stowage categories 6 through 15 will be eliminated and
stowage categories 1 through 5 will be modified. Changes to the explosive stowage
categories are necessary because, as part of this final rule, PHMSA is removing magazine
stowage Types “A,” “C,” and special stowage from Part 176 with the consolidation of
authorized explosive stowage categories. The authorized explosive stowage categories
will be replaced with a new term of art “Closed cargo transport units for Class 1
(explosives).” Included in this definition are freight containers or transport vehicles that
are structurally serviceable in accordance with§ 176.172, portable magazines conforming
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