---
kind: "section"
citation: "40 C.F.R. § 61.201"
title: "40"
number: "61.201"
heading: "Definitions."
url: "https://uscodex.org/cfr/40/61.201"
---

# §61.201. Definitions.


As used in this subpart, all terms not defined here have the meaning given them in the Clean Air Act or [subpart A of part 61](/cfr/40/part61-subpartA.md). The following terms shall have the following specific meanings:

- (a) Inactive stack means a stack to which no further routine additions of phosphogypsum will be made and which is no longer used for water management associated with the production of phosphogypsum. If a stack has not been used for either purpose for two years, it is presumed to be inactive.
- (b) **Phosphogypsum—** is the solid waste byproduct which results from the process of wet acid phosphorus production.
- (c) **Phosphogypsum stacks—** or stacks are piles of waste resulting from wet acid phosphorus production, including phosphate mines or other sites that are used for the disposal of phosphogypsum.

## Notes

### Source

Source: 57 FR 23317, June 3, 1992, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 38 FR 8826, Apr. 6, 1973, unless otherwise noted.