---
kind: "section"
citation: "40 C.F.R. § 420.21"
title: "40"
number: "420.21"
heading: "Specialized definitions."
url: "https://uscodex.org/cfr/40/420.21"
---

# §420.21. Specialized definitions.


As used in this subpart:

- (a) For the sintering subcategory, the term product means sinter agglomerated from iron-bearing materials.
- (b) The term dry air pollution control system means an emission control system that utilizes filters to remove iron-bearing particles (fines) from blast furnace or sintering off-gases.
- (c) The term minimum level (ML) means the level at which the analytical system gives recognizable signals and an acceptable calibration point. For 2,3,7,8-tetrachlorodibenzofuran, the minimum level is 10 pg/L per EPA Method 1613B for water and wastewater samples.
- (d) The term pg/L means picograms per liter (ppt = 1.0 × 10-12 gm/L).
- (e) The term sintering means a process for agglomerating iron-bearing materials into small pellets (sinter) that can be charged to a blast furnace.
- (f) The term wet air pollution control system means an emission control system that utilizes water to clean process or furnace off-gases.

## Notes

### Amendments

[67 FR 64264, Oct. 17, 2002]

### Authority

Authority: 33 U.S.C. 1311, 1314, 1316, 1317, 1318, 1342, and 1361.

### Source

Source: 47 FR 23284, May 27, 1982, unless otherwise noted.

### Amendments

[67 FR 64264, Oct. 17, 2002]