### Question
What does heavy petroleum fuel oil mean?


### Answer
**Heavy petroleum fuel oil** has the following meaning in *15 U.S.C. § 717y*:

> number 4, 5, or 6 fuel oil which is domestically refined

#### Citation:
  - *15 U.S.C. § 717y*
  - Heading: **CHAPTER 15B-NATURAL GAS**

