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Taking Toxics Out of the Air

Summaries of EPA's Final Air Toxics MACT Rules

Portland Cement Manufacturing
Final rule published June 14, 1999

    Air Toxics Emissions Bar Graph: Pre-rule 290 tons compared to Post-rule 200 tons
  • Portland cement is manufactured by grinding and heating a mixture of raw materials (e.g., limestone, clay, iron ore) in a rotary kiln. The kiln is fired by a variety of fuels, including coal, oil, gas, coke, and/or various waste materials. After firing, the product (called clinker) is cooled and then mixed with gypsum to produce portland cement.
  • A number of harmful air pollutants, including air toxics, particulate matter, and hydrocarbons, are released during portland cement manufacturing. Most of these result from fuel combustion in the kiln and from heating and handling of raw materials. The health impacts of these pollutants include an increased risk of respiratory and cardiovascular diseases and cancer.
  • Particulate Matter Emissions Bar Graph: Pre-rule 24,800 tons compared to Post-rule 20,600 tons
  • This rule sets emission limits for kilns, clinker coolers, and materials handling facilities, and includes new emission measurement methods. In complying with this rule, facility owners and operators have the flexibility to determine how emission limits will be met.
  • Approximately 110 portland cement manufacturing facilities nationwide will be regulated under this rule. The rule will reduce air toxics emissions by approximately 90 tons per year (a 31 percent reduction), particulate matter emissions by 4,200 tons annually (a 17 percent reduction), and hydrocarbons emissions by 220 tons annually (a 38 percent reduction).
  • Hydrocarbons Emissions Bar Graph: Pre-rule 580 tons compared to Post-rule 360 tons



Oil and Natural Gas Production and Natural Gas Transmission and Storage
Two final rules published June 17, 1999
    Air Toxics Emissions from Oil and Natural Gas Production Bar Graph: Pre-rule 72,000 tons compared to Post-rule 41,000 tons
  • Emissions of air toxics from oil and natural gas production and natural gas transmission and storage occur during separation, upgrade, transport, and storage of crude oil, condensate, natural gas, and related products. Emissions also occur as a result of vapor leaks from pumps, compressors, valves, flanges, and other equipment.
  • The affected facilities can release a variety of air toxics, including benzene (a known human carcinogen) and other volatile organic compounds (VOCs) suspected to cause cancer or other serious health effects such as birth defects or reproductive effects. VOCs also contribute to the formation of ground-level ozone, the primary constituent of smog. In addition, the affected facilities can release methane, a potent greenhouse gas.
  • Air Toxics Emissions from Natural Gas Transmission and Storage Bar Graph: Pre-rule 2,400 tons compared to Post-rule 1,970 tons
  • EPA's rules require controls for the following emission points at oil and natural gas production facilities: process vents at some glycol dehydration units, tanks with flashing emission potential, and some fugitive emission sources. Natural gas transmission and storage facilities will be required to control emissions from process vents at some glycol dehydration units.
  • In an effort to increase flexibility, EPA is encouraging facility owners and operators to use pollution prevention techniques to reduce emissions from process vents at glycol dehydration systems-the largest single air pollutant emission point at oil and natural gas production facilities.
  • The oil and natural gas production rule will affect approximately 440 facilities nationwide. It will reduce air toxics emissions by an estimated 31,000 tons annually (a 43 percent reduction), VOC emissions by 67,000 tons annually (a 45 percent reduction), and methane emissions by 7,700 tons annually (a 33 percent reduction).
  • The natural gas transmission and storage rule will affect approximately seven facilities nation-wide. It will reduce air toxics emissions by an estimated 430 tons annually (an 18 percent reduction), VOC emissions by 610 tons annually (a 19 percent reduction), and methane emissions by 250 tons annually (a 19 percent reduction).

Steel PicklingHydrochloric Acid Emissions Bar Graph: Pre-rule 3,300 tons compared to Post-rule 800 tons
Final rule published June 22, 1999

  • Steel pickling is a process in which an acid solution is used to remove the oxide scale that forms on steel as it cools from a molten state.
  • Hydrochloric acid and chlorine can be released to the atmosphere during the steel pickling process. Hydrochloric acid is emitted from processing tanks used in continuous and batch pickling lines, from acid regeneration plants, and from storage tanks containing virgin or regenerated acid. Chlorine is emitted from acid regeneration plants.
  • Chronic exposure to hydrochloric acid can cause inflammation of the stomach, respiratory system, and skin, as well as sensitivity to sunlight. Acute exposure to high levels of chlorine can result in vomiting, chest pain, lung problems, and even death. At lower levels, chlorine is a potent irritant to the eyes, the upper respiratory tract, and the lungs.
  • EPA's rule establishes limits for hydrochloric acid emissions from pickling lines, acid regeneration plants, and acid storage tanks. It also establishes limits for chlorine emissions from acid regeneration plants. The rule offers flexibility to facility operators by providing cost-effective options for both emissions control and monitoring.
  • This rule will affect approximately 62 steel pickling plants and 8 acid regeneration plants. When fully implemented, the rule will reduce hydrochloric acid emissions by approximately 2,500 tons per year (a 76 percent reduction from current levels) and chlorine emissions by 8.2 tons per year (a 30 percent reduction from current levels). The controls required by this rule will also reduce particulate matter emissions.

Pesticide Active Ingredient Production
Final rule published June 23, 1999

  • Pesticide active ingredients (PAIs) are used in the manufacture of insecticide, herbicide, and fungicide products. These products are typically used in the agricultural industry for treating insects, rodents, weeds, and other pests.
  • A variety of air toxics, including toluene, methanol, and hydrochloric acid, can be released to the atmosphere during production of PAIs.
  • EPA's rule affects the following points in the PAI production process: process vents, storage vessels, wastewater and associated treatment residuals, heat exchange systems, and certain types of equipment. The rule allows facilities the flexibility to meet emissions limits for process vents by using either an add-on control device or a pollution-prevention alternative.
  • Currently, there are approximately 78 PAI production facilities that will be affected by this rule. When fully implemented, the rule will reduce emissions of air toxics by approximately 2,755 tons per year, a 65 percent reduction from current levels.

Generic Rule (for Acetal Resin Production, Acrylic and Modacrylic Fiber Production, Hydrogen Fluoride Production, and Polycarbonate Production)
Four final rules published June 29, 1999

  • These rules set technology-based emission limits for several categories that have five or fewer facilities nationwide.
  • The facilities regulated by these rules manufacture a variety of components, including thermoplastics used in industrial applications and commercial articles; synthetic fibers used in the textile, sporting goods, and aviation industries; polycarbonates used in electrical components and automotive parts; and fluoride compounds.
  • A variety of air toxics are sometimes released to the atmosphere during the manufacture of these products. These air toxics include formaldehyde, methanol, and the volatile organic compounds methylene chloride, ethyl chloride, and phosgene.
  • EPA's rules will control emissions for all of the categories at similar phases of the manufacturing process. These phases include storage tanks, process vents, equipment leaks, and wastewater.
  • The rules will ensure that the nine affected facilities maintain or develop emission controls.

Publicly Owned Treatment Works
Final rule published October 26, 1999

  • Publicly owned treatment works (POTW) treat wastewater received from residential, commercial, and industrial sources. POTW can release air toxics in the form of volatile organic compounds in wastewater.
  • The primary air toxics emitted by POTW include xylenes, methylene chloride, toluene, ethyl benzene, chloroform, tetrachloroethylene, benzene, and naphthalene. Each of these air toxics can cause adverse health effects provided sufficient exposure. For example, exposure to methylene chloride (a probable human carcinogen) can adversely affect the central nervous system, while benzene is known to cause cancer in humans.
  • EPA's rule will reduce air toxics emissions from new or reconstructed POTW that are major sources of air emissions. EPA is not requiring additional controls on existing POTW.
  • Some POTW treat wastewater from industrial sources whose waste streams are already regulated by industrial air toxics rules. By treating their regulated waste streams at a POTW, these industrial sources are able to comply with these other air toxics rules. Under the new POTW rule, plants that treat regulated waste streams from industrial sources are classified as industrial POTW. All other treatment plants are classified as non-industrial POTW.
  • Under EPA's rule, new or reconstructed non-industrial POTW will need to either include air pollution controls on certain wastewater treatment units or demonstrate through pollution prevention techniques an equivalent reduction in emissions. New or reconstructed industrial POTW must comply with the non-industrial standards, or with all other air toxics regulations applicable to the industrial sources whose wastewater they are treating, whichever is more stringent.
  • EPA estimates that 20 to 30 non-industrial POTW would need to control air toxics emissions if they elected to reconstruct their existing facilities or build a new facility. EPA estimates that fewer than five POTW currently meet the definition of industrial POTW. The rule is not expected to require additional reductions from these sources.

Amino Resins and Phenolic Resins Production
Final rule published January 20, 2000

  • Amino/phenolic resins are primarily used in the manufacture of plywood, particle board, adhesives, wood furniture, and plastic parts.
  • A number of toxic air pollutants, including formaldehyde (a probable human carcinogen), phenol, methanol, xylene, and toluene, are released during the resin manufacturing process.
  • EPA's rule establishes emission limits or control efficiency requirements for several emission points: reactor batch process vents, non-reactor batch process vents, continuous process vents, storage tanks, equipment leaks, and heat exchange systems. The rule encourages the use of pollution prevention measures and provides flexibility by allowing the use of a variety of control strategies rather than specific control devices.
  • The rule affects new and existing amino/phenolic resin manufacturing facilities. EPA has identified 100 existing facilities that may be affected. The rule will reduce air toxics emissions by approximately 360 tons per year, a 51 percent reduction from 1992 levels.

Secondary Aluminum Production
Final rule published March 23, 2000

  • Secondary aluminum plants recover aluminum from beverage cans, foundry returns, and other aluminum scrap. These facilities release air toxics during both preprocessing operations (such as aluminum scrap shredding, drying, and decoating) and furnace operations (such as aluminum melting, refining, and alloying).
  • Secondary aluminum plants emit a variety of toxic air pollutants. These air toxics may include up to 11 metals, organic compounds, and acid gases such as hydrogen chloride and chlorine. The health effects associated with exposure to these air toxics can include cancer, respiratory irritation, and damage to the nervous system.
  • EPA's rule establishes emission standards for metals, dioxin/furans, organic hazardous air pollutants, and acid gases for larger secondary aluminum plants. The rule also establishes standards for dioxin/furan emissions from smaller secondary aluminum plants.
  • Affected sources can achieve the emission reductions required by the rule through the use of pollution-control equipment and/or through a variety of pollution-prevention measures, including work practices and operating practices. The rule provides flexibility to the industry by offering alternative compliance and monitoring options. To reduce monitoring and emissions testing costs, the rule uses particulate matter as a surrogate for metals, total hydrocarbons as a surrogate for organics, and hydrogen chloride as a surrogate for total emissions of hydrogen chloride, chlorine, and hydrogen fluoride.
  • The rule will affect 80 large secondary aluminum plants. Hundreds of smaller plants may be subject to limitations on emissions of dioxin/furans. The rule will reduce nationwide emissions of air toxics by about 12,420 tons per year, a reduction of nearly 70 percent from current levels. In particular, hydrogen chloride emissions will be reduced by about 12,370 tons per year or by 73 percent, and emissions of metals will be reduced by about 40 tons per year, a reduction of over 60 percent from current levels.

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