### Question
What is the definition of hazardous material?


### Answer
The definition of **hazardous material** is as follows in *39 U.S.C. § 3001*:

> a substance or material designated by the Secretary of Transportation under section 5103(a) of title 49

#### Citation:
  - *39 U.S.C. § 3001*
  - Heading: **PART IV-MAIL MATTER > CHAPTER 30-NONMAILABLE MATTER**

