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223 Hazardous Materials Warning Labels and Markings

Most mailable hazardous materials fall in the ORM-D (other regulated materials), consumer commodity, or mailable limited quantity categories. ORM-D materials (surface only) may include an ORM-D marking or a Department of Transportation (DOT) square-on-point marking. Most materials intended for air transportation must bear a DOT square-on-point marking, including the symbol “Y”, and may require a specific DOT diamond–shaped hazardous materials warning label and other markings. See Chapter 3, Exhibit 325.1, and Exhibit 325.2a, for more specific information on hazardous materials warning labels and marking requirements.