EPA Proposes the Remaining Ten MACT Rules

For more information, contact Roger Brower at 410.312.7907. 

On November 26, 2002 EPA proposed the last 10 toxic air pollutant standards required under the Clean Air Act. All but one of the proposed standards were published in the Federal Register by January 22, 2003.

The source categories addressed are (scroll down for category descriptions):

  • auto and light duty truck surface coating;
  • combustion turbines;
  • industrial, commercial and institutional boilers and process heaters;
  • iron and steel foundries;
  • lime manufacturing;
  • metal can surface coating;
  • plywood and composite wood products manufacturing;
  • primary magnesium refining;
  • reciprocating internal combustion engines;
  • and taconite iron ore processing.

EPA will take public comment on the proposals for 60 days after publication in the Federal Register. However, EPA reduced the comment period to 30 days for the stationary combustion turbines, metal cans surface coating, and primary magnesium refining proposals (http://www.epa.gov/fedrgstr/EPA-AIR/2003/January/Day-03/a32718.htm).

For five proposals (reciprocating internal combustion engines, automobiles and light-duty trucks surface coating, plywood and composite wood products, industrial/commercial/institutional boilers and process heaters, and stationary combustion turbines), EPA is specifically requesting comment on options to reduce implementation costs.

The 1990 Clean Air Act Amendments (CAAA) require EPA to use a technology-based/performance-based approach to significantly reduce emissions of toxic air pollutants from major sources of air pollution, followed by a risk-based approach to address any remaining (residual) risks. Toxic air pollutants are those pollutants that are known to or suspected to cause cancer or other serious health effects. The 1990 CAAA list 188 toxic air pollutants.

Under the technology-based approach, EPA develops standards for controlling toxic air pollutant emissions from each major type of facility within an industry group (or "source category"). These maximum achievable control technology (MACT) standards are based on emissions levels that are already being achieved by the better-controlled (and lower-emitting) sources in an industry. In setting MACT standards, EPA does not generally prescribe a specific control technology, but, whenever feasible, sets a performance level based on existing, successful control technology or other practices.

Eight years after each MACT standard is issued, EPA must assess the remaining health risks from source categories. If necessary, EPA may implement additional standards that address any significant remaining risk. A brief summary of the proposed rules is given below:

Automobiles & light-duty trucks surface coating This rule affects any new, reconstructed, or existing automobile and light-duty truck manufacturing facility that is a major source of toxic air pollutants. The primary pollutants reduced include toluene, xylene, glycol ethers, MEK, MIBK, ethylbenzene and methanol. The rule proposes organic HAP emission limits and material content limits as well as operating limits.

Stationary combustion turbines This rule affects any equal to or larger than 1 MW, new or reconstructed combustion turbine and existing lean premix combustion turbines at a major source of toxic air pollutants. The primary pollutants reduced include formaldehyde, toluene, acetaldehyde and benzene. The rule requires 95% CO control if an oxidation catalyst is used, or a formaldehyde emission level of 43 ppbvd if an oxidation catalyst is not used.

Industrial, commercial, and institutional boilers and process heaters This rule affects any new or existing boiler and process heater at a major source of toxic air pollutants. The primary pollutants reduced include hydrogen chloride, lead, arsenic, manganese, nickel, chromium, cadmium, mercury and hydrogen fluoride. The rule proposes emission limits of particulate matter (or total selected metals), hydrogen chloride, mercury and carbon monoxide for various-sized boilers and heaters firing different fuels, as well as operating limits.

Iron and steel foundries This rule affects any new or existing metal casting departments and mold and core making departments at an iron and steel foundry that is a major source of toxic air pollutants. The primary pollutants reduced include benzene, chromium, dioxin, formaldehyde, lead, manganese, methanol, naphthalene, nickel, and triethylamine. Emission limits for metal and organic HAP are proposed along with operating limits for capture systems and control devices and work practice requirements.

Lime manufacturing plants This rule affects new and existing lime manufacturing plants that are, or are part of or collocated with, a major source of toxic air pollutants. The primary pollutants reduced include arsenic, cadmium, chromium, nickel and hydrogen chloride. The rule proposes particulate matter emission limits for lime kilns and coolers, as well as particulate emissions and opacity limits for certain types of material processing operations.

Metal cans surface coating This rule affects any new, reconstructed or existing metal can facility that is a major source of toxic air pollutants that use more than 1,500 gallons of coatings per year. The primary pollutants reduced include ethylene glycol butyl ether (EGBE), xylene, glycol ethers, MEK, hexane, and MIBK. The rule proposes organic HAP emission limits for various metal can coating and sealing processes. Several compliance options are available in the proposed rule. The facility could comply by applying materials (coatings and thinners) that meet the emission limit, either individually or collectively, use a capture system and add-on control equipment, or use a combination of both approaches.

Plywood and composite wood products This rule affects new and existing plywood and composite wood product facilities that are major sources of toxic air pollutants. The primary pollutants reduced include methanol, formaldehyde, acrolein, acetaldehyde, phenol and propionaldehyde. The proposed rule provides several options for compliance: 1) installation of control systems with at least 90% control; 2) production-based limits; and 3) emissions averaging that allows control of emissions from a group of sources collectively.

Primary magnesium refining This rule affects any new or existing primary magnesium refinery that is a major source of toxic air pollutants. Currently the only primary magnesium refinery in the U.S. is U.S. Magnesium Corporation in Rowley, UT. The primary pollutants reduced include chlorine, hydrochloric acid and dioxin/furans. The emissions limits in the proposed rule were adopted from the plant's Title V permit issued by the State of Utah Department of Environmental Quality. Various combinations of venturi and packed bed scrubbers are used for control.

Stationary reciprocating internal combustion engines This rule affects all new, and certain existing, stationary reciprocating internal combustion engines above 500 horsepower that are located at a major source of toxic air pollutants. The primary pollutants reduced include formaldehyde, acrolein, methanol and acetaldehyde. The rule proposes emission limits and control levels for various types of new and existing engines. Requirements for new and existing 4SRB engines include NSCR systems achieving 75% control of formaldehyde, or other systems resulting in formaldehyde emissions less than or equal to 350 ppb. Requirements for new 2SLB and 4SLB, and compression engines, include carbon monoxide catalytic oxidation systems achieving 60%, 93%, and 60% CO control, respectively, or other means resulting in formaldehyde emissions less than or equal to 17 ppm, 14 ppm and 580 ppm, respectively.

Taconite iron ore processing This rule affects new and existing taconite iron ore processing facilities that are major sources of toxic air pollutants. The primary pollutants reduced include manganese, chromium, cobalt, arsenic and lead. The proposed rule includes particulate matter emission limits, work practice standards, and operating limits for control devices.

EPA links for these categories:

If you have any questions, feel free to contact Roger Brower at 410.312.7907 or rbrower@zephyrenv.com.