# 40 C.F.R. § 61.201 (2026): Definitions

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_201

## Section

- **Citation:** 40 C.F.R. § 61.201 (2026)
- **Heading:** Definitions
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 40 CFR: Protection of Environment / Chapter I / Part 61 / Subpart R / § 61.201: § 61.201   Definitions.

## Text

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. 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.

## Nearby sections

- [40 C.F.R. § 61.200 (2026) § 61.200   Designation of facilities.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_200.md)
- [40 C.F.R. § 61.201 (2026) § 61.201   Definitions.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_201.md)
- [40 C.F.R. § 61.202 (2026) § 61.202   Standard.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_202.md)
- [40 C.F.R. § 61.203 (2026) § 61.203   Radon monitoring and compliance procedures.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_203.md)
- [40 C.F.R. § 61.204 (2026) § 61.204   Distribution and use of phosphogypsum for outdoor agricultural purposes.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_204.md)
- [40 C.F.R. § 61.205 (2026) § 61.205   Distribution and use of phosphogypsum for indoor research and development.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_205.md)
- [40 C.F.R. § 61.206 (2026) § 61.206   Distribution and use of phosphogypsum for other purposes.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_206.md)
- [40 C.F.R. § 61.207 (2026) § 61.207   Radium-226 sampling and measurement procedures.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_207.md)
- [40 C.F.R. § 61.208 (2026) § 61.208   Certification requirements.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_208.md)
- [40 C.F.R. § 61.209 (2026) § 61.209   Required records.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_209.md)
- [40 C.F.R. § 61.210 (2026) § 61.210   Exemption from the reporting and testing requirements of 40 CFR 61.10.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_210.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T40_P61_S61_201. Check the current official text before relying on it. Not legal advice.