For the purposes of this rule, the following definitions apply:

1. (1) "Aluminum manufacturing" means the electrolytic reduction of alumina (aluminum oxide) to aluminum.
2. (2) "Emission" means a release into the outdoor atmosphere of total fluorides.
3. (3) "Existing primary aluminum reduction plant" means any facility manufacturing aluminum, by electrolytic reduction, which was in existence and operating on February 26, 1982.
4. (4) "Owner or operator" means any person who owns, leases, operates, controls, or supervises an existing primary aluminum reduction plant.
5. (5) "Pot" means a reduction cell.
6. (6) "Potroom" means a building unit which houses a group of electrolytic cells in which aluminum is produced.
7. (7) "Potroom group" means an uncontrolled potroom, a potroom which is controlled individually as a group of potrooms or potroom segments ducted to a common control system.
8. (8) "Total fluorides" means all fluoride compounds as measured by methods approved by the department.

Authorizing statute(s): 75-2-111, 75-2-203, MCA

Implementing statute(s): 75-2-203, MCA

History: NEW, 1982 MAR p. 390, Eff. 2/26/82; AMD, 1989 MAR p. 270, Eff. 2/10/89; TRANS, from DHES, 1996 MAR p. 2285.