MACT Standards Proposed for the Iron and Steel Industry

EPA has proposed national emission standards for hazardous air pollutants for integrated iron and steel manufacturing facilities.

The primary processes of interest because of their potential to generate HAP emissions include sinter plants, blast furnaces that produce iron, and basic oxygen process furnaces (BOPF) that produce steel. There are also several ancillary processes, including hot metal transfer, desulfurization, slag skimming, and ladle metallurgy. Iron and steel are produced at 20 plant sites in the United States that have a total of 39 blast furnaces, 50 BOPF and 9 sinter plants. Integrated iron and steel plants are located in ten States; however, the majority of the iron and steel is produced in Indiana, Ohio and Illinois.

The proposed rule covers emissions from the sinter plant windbox exhaust, discharge end, and sinter cooler; the blast furnace casthouse; and the BOPF, BOPF shop roof monitor, and BOPF ancillary operations (hot metal transfer, hot metal desulfurization, slag skimming and ladle metallurgy).

The proposed rule includes PM emission limits and opacity limits as well as operating limits for capture systems and control devices. Particulate matter and opacity serve as a surrogate measure of HAP emissions.

The proposed PM emission limit for the sinter plants windbox exhaust stream is 0.3 pounds per ton (lb/ton) of product sinter. The proposed rule limits PM emissions from a discharge end to 0.02 gr/DSCF for an existing plant and 0.01 gr/DSCF at a new plant.

The proposed PM emission limit for a blast furnace control device applied to emissions from a casthouse is 0.009 gr/DSCF for the casthouse at a new or existing blast furnace. The proposed opacity limits are 20 percent for a casthouse at an existing blast furnace and 15 percent for a casthouse at a new blast furnace (both 6-minute averages).

For BOPF with closed hood systems, EPA is proposing a PM emission limit of 0.024 gr/DSCF which would apply only during periods of primary oxygen blow. For BOPF with open hood systems, EPA is proposing a PM emission limit of 0.019 gr/DSCF which would apply during all periods of the steel production cycle (4).