---
kind: "section"
citation: "40 C.F.R. § 57.301"
title: "40"
number: "57.301"
heading: "General requirements."
url: "https://uscodex.org/cfr/40/57.301"
---

# §57.301. General requirements.


Each NSO shall require an interim level of sulfur dioxide constant controls to be operated at the smelter, unless a waiver of this requirement has been granted to the owner under [subpart H](/cfr/40/subpartH.md) of this part. Except as otherwise provided in [§ 57.304](/cfr/40/57.304.md), the interim constant controls shall be properly operated and maintained at all times. The NSO shall require the following gas streams to be treated by interim constant controls:

- (a) In copper smelters, off-gases from fluidized bed roasters, flash furnaces, NORANDA reactors, electric furnaces and copper converters;
- (b) In lead smelters, off-gases from the front end of the sintering machine and any other sinter gases which are recirculated;
- (c) In zinc smelters, off-gases from mult-hearth roasters, flash roasters and fluidized bed roasters; and
- (d) **In all primary nonferrous smelters, all other strong SO<I>2</I> streams.**
- (e) In all primary nonferrous smelters, any other process streams which were regularly or intermittently treated by constant controls at the smelter as of August 7, 1977.

## Notes

### Authority

Authority: Secs. 110, 114, 119, 301, Clean Air Act, as amended (42 U.S.C. 7410, 7414, 7419, and 7601); sec. 406 of Pub. L. 95-95.

### Source

Source: 50 FR 6448, Feb. 15, 1985, unless otherwise noted.