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334 Mailable Limited Quantity

Mailable Limited Quantity is a hazardous material in hazard Classes 4, 5, 8, or portions of 9 that presents a limited hazard during transportation (specifically air transport), and is mailable in USPS air networks under certain conditions and in limited quantities. The Mailable Limited Quantity category is unique to the United States, and its use is prohibited with international shipments.

It is the responsibility of the mailer to know the correct DOT hazard class of a hazardous material before mailing (see 323).

When assistance is needed to determine eligibility for mailing, the mailer may request a ruling from the PCSC (215.2 and DMM 601.10.6).