Affirmative defense means, in the context of an enforcement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are independently and objectively evaluated in a judicial or administrative proceeding.

Bag leak detection system means a system that is capable of continuously monitoring relative particulate matter (dust) loadings in the exhaust of a baghouse in order to detect bag leaks and other upset conditions. A bag leak detection system includes, but is not limited to, an instrument that operates on triboelectric, light scattering, light transmittance, or other effect to continuously monitor relative particulate matter loadings.

Blast furnace means any reduction furnace to which sinter is charged and which forms separate layers of molten slag and lead bullion.

Building means a roofed and walled structure with limited openings to allow access and egress for people and vehicles.

Charging location means the physical opening through which raw materials are introduced into a sinter machine, blast furnace, or dross furnace.

Dross furnace means any smelting furnace to which drosses are charged and which chemically and physically separates lead from other impurities.

Drossing and refining kettle means an open-top vessel that is constructed of cast iron or steel and is indirectly heated from below and contains molten lead for the purpose of drossing, refining, or alloying lead. Included are pot furnaces, receiving kettles, and holding kettles.

Fugitive dust source means a stationary source of hazardous air pollutant emissions at a primary lead processor resulting from the handling, storage, transfer, or other management of lead-bearing materials where the source is not part of a specific process, process vent, or stack. Fugitive dust sources include roadways, storage piles, materials handling transfer points, and materials transport areas.

Furnace area means any area of a primary lead processor in which a blast furnace or dross furnace is located.

Lead refiner means any facility that refines lead metal that is not located at a primary lead processor.

Lead remelter means any facility that remelts lead metal that is not located at a primary lead processor.

Malfunction means any sudden, infrequent, and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner which causes, or has the potential to cause, the emission limitations in an applicable standard to be exceeded. Failures that are caused in part by poor maintenance or careless operation are not malfunctions.

Materials storage and handling area means any area of a primary lead processor in which lead-bearing materials (including ore concentrate, sinter, granulated lead, dross, slag, and flue dust) are stored or handled between process steps, including areas in which materials are stored in piles, bins, or tubs, and areas in which material is prepared for charging to a sinter machine or smelting furnace or other lead processing operation.

Operating time means the period of time in hours that an affected source is in operation beginning at a startup and ending at the next shutdown.

Plant operating time means the period of time in hours that either a sinter machine or blast furnace is in operation.

Plant roadway means any area of a primary lead processor that is subject to vehicle traffic, including traffic by forklifts, front-end loaders, or vehicles carrying ore concentrates or cast lead ingots. Excluded from this definition are employee and visitor parking areas, provided they are not subject to traffic by vehicles carrying lead-bearing materials.

Primary lead processor means any facility engaged in the production of lead metal from lead sulfide ore concentrates through the use of pyrometallurgical or other techniques.

Process fugitive source means a source of hazardous air pollutant emissions at a primary lead processor that is associated with lead smelting, processing or refining but is not the primary exhaust stream and is not a fugitive dust source. Process fugitive sources include sinter machine charging locations, sinter machine discharge locations, sinter crushing and sizing equipment, furnace charging locations, furnace taps, and drossing kettle and refining kettle charging or tapping locations.

Refining and casting area means any area of a primary lead processor in which drossing or refining operations occur, or casting operations occur.

Secondary lead smelter means any facility at which lead-bearing scrap material, primarily, but not limited to, lead-acid batteries, is recycled into elemental lead or lead alloys by smelting.

Shutdown means the cessation of operation of an affected source for any purpose.

Sinter machine means any device in which a lead sulfide ore concentrate charge is heated in the presence of air to eliminate sulfur contained in the charge and to agglomerate the charge into a hard porous mass called sinter.

Sinter machine area means any area of a primary lead processor where a sinter machine, or sinter crushing and sizing equipment is located.

Sinter machine discharge end means the physical opening at the end of a sinter machine where the sinter exits the sinter machine.

Startup means the setting in operation of an affected source for any purpose.

Tapping location means the opening thru which lead and slag are removed from the furnace.

Tapping location means the opening through which lead and slag are removed from the furnace.