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Outdoor Air - Industry, Business, and Home: Industrial, Commercial, and Institutional (ICI) Boilers - Additional Information

Information provided for informational purposes onlyNote: EPA no longer updates this information, but it may be useful as a reference or resource.

This information will help you gain a better understanding of ICI boilers. The sections below provide more information on this topic:

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What are ICI boilers?

  • Boilers are combustion devices uses to produce steam or heat water.
  • Steam is produced in boilers by heating water until it vaporizes. The steam is then used to run processes or machinery or to produce heat or electricity.
  • There are literally thousands of boilers currently being used in the United States throughout a wide variety of industries.
  • A boiler system includes the boiler itself, associated piping and valves, operation and safety controls, water treatment system, and peripheral equipment such as pollution control devices, economizers, or superheaters.
  • Most boilers are made of steel, cast iron, or copper.
  • The primary fuels used by boilers are coal, oil, and natural gas, but some use electricity, waste gases, or biomass.
  • Industrial boilers are used in all major industrial sectors but primarily by the paper products, chemical, food, and petroleum industries.
  • EPA estimates that the heat input capacity for these boilers is typically between 10 and 250 MMBtu/hr. However, larger industrial boilers do exist and are similar to utility boilers.
  • Commercial/Institutional boilers are generally smaller than the industrial units with heat input capacities generally below 10 MMBtu/hr. These units normally supply the steam and hot water for space heating in a wide range of locations, including wholesale and retail trade, office buildings, hotels, restaurants, hospitals, schools, museums, government buildings, and airports.

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What are the health effects of pollutants emitted from ICI boilers?

ICI boilers emit pollutants such as hazardous air pollutants (HAPs), particle pollution, and volatile organic compounds (VOC). These pollutants can contribute to health problems that may affect employees, residents, and the community. While Federal, state, local, and Tribal regulations limit the amount of emissions from ICI boilers, dangerous releases of HAPs can occur if an ICI boiler does not operate in compliance with regulations.

  • Emissions from ICI boilers are a function of the type and quantity of primary fuel burned in the boiler unit, the type of boiler, and emissions controls.
  • Boilers emit a variety of pollutants, including those associated with combustion processes and HAPs, such as:
    • Nitrogen oxides (NOx).
    • Sulfur dioxide (SO2).
    • Particle pollution.
    • Carbon monoxide (CO).
    • Formaldehyde.
    • Polynuclear aromatic hydrocarbons (PAHs).
    • Lead
    • Hydrogen Chloride (HCl).
    • Cadmium.
    • Mercury.
    • Dioxin/furans.
  • Nitrogen Oxides
    • Nitrogen oxides can react in the air to form acid rain, ground-level ozone (smog), and other toxic chemicals.
    • Nitrogen oxides are one of the chief ingredients of ground-level ozone, which has been linked to a number of respiratory effects. EPA has developed a Web site on ground-level ozone as well as nitrogen oxides .
  • Sulfur Dioxides
    • Sulfur dioxides can react with other chemicals to form particle pollution, which can lodge deep in the lungs and cause respiratory problems and possibly death.
    • Sulfur dioxides can cause temporary breathing difficulties for people who have asthma and are active outdoors.
    • Longer-term exposure to high concentrations of sulfur dioxide and particles can cause respiratory illness and aggravate existing heart conditions.
    • EPA has developed an extensive Web site related to sulfur dioxide.
  • Particle Pollution
    • Breathing particle pollution can cause respiratory problems and other harmful health effects. EPA has developed a Web site on particle pollution.
  • Carbon Monoxide
    • Low amounts of carbon dioxide can impact those people with cardiovascular problems.
    • People who inhale high amounts of carbon dioxide can encounter central nervous system problems such as vision problems, reduced ability to work or learn, reduced manual dexterity, and difficulty in performing tasks.
    • Carbon monoxide also contributes to ground-level ozone (smog).
    • EPA has developed an extensive Web site related to carbon monoxide.
  • Formaldehyde
    • Short-term exposure to formaldehyde can cause eye, throat, and nose irritation, coughing, wheezing, chest pains, and bronchitis.
    • Long-term exposure to formaldehyde can cause eye and respiratory tract irritation, reproductive and developmental problems.
    • Formaldehyde may be a probable human carcinogen.
    • EPA's Health Effects Notebook has more information about formaldehyde.
  • PAHs
    • PAHs are caused by the incomplete combustion of fuel.
    • Some PAHs can cause cancer.
  • Lead
    • Lead is a very toxic metal and can cause adverse health effects at low levels.
    • Short-term exposure can cause brain damage, kidney damage, and gastrointestinal distress.
    • Long-term exposure can impact the blood, blood pressure, central nervous system, kidneys, and Vitamin D metabolism.
    • Children are especially susceptible to long-term lead exposure, which can result in slow cognitive development and reduced growth.
    • EPA's Health Effects Notebook has more information about lead.
  • Hydrogen Chloride
    • Hydrogen chloride (also known as hydrochloric acid) is produced by the burning of fuels containing chloride.
    • Short-term exposure to hydrogen chloride can cause eye, nose, and respiratory tract irritation, and inflammation and pulmonary edema.
    • Long-term occupational exposure to hydrogen chloride can cause gastritis, chronic bronchitis, dermatitis, photosensitization, and possibly dental discoloration and erosion.
    • EPA's Health Effects Notebook contains more information on hydrogen chloride.
  • Cadmium
    • Cadmium is emitted during the burning of fossil fuels.
    • Short-term exposure to cadmium can irritate the lungs.
    • Long-term exposure can cause kidney and respiratory problems.
    • EPA's Health Effects Notebook contains more information on cadmium.
  • Mercury
    • Mercury is emitted during the burning of fossil fuels.
    • Exposure to mercury can result in nervous system and kidney damage as well as developmental damage.
    • The EPA's Health Effects Notebook has more information on the health effects of mercury.
  • Dioxin/furans
    • Dioxins are released when items containing even trace amounts of chlorine are burned.
    • Dioxins are persistent, bioaccumulative toxins (PBTs). They remain in the environment for extended periods of time and increase in concentration as they move up the food chain.
    • Dioxins enter the food chain by settling out of the air into water and onto vegetation.
    • Dioxins can cause immune system suppression, disruption of hormonal systems, and cancer.
    • The EPA has developed an extensive Web site related to dioxins.

For more information on the toxicity of these pollutants, check out information on the Integrated Risk Information System (IRIS). EPA also has more information available at its Air Toxics Web site.

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How can I help ICI boiler owners and operators reduce air pollution?

  • Make Connections
    • Get to know ICI boiler owners and operators. They know best about the processes used at their facilities and the regulations with which they must comply.
    • Keep local media aware of progress by sending them updates. Publicity can reward success and attract more public involvement.
  • Make a Plan
    • One idea is to form a work group that includes local owners and operators to develop and implement workable pollution reduction plans.
    • Encouraging them to conduct an energy audit is a good start to identifying cost-effective pollution reduction measures.
  • Locate Resources
    • Find state, local, and Tribal contacts.
    • Use the resources listed on these Web pages to get help with analysis, technical information, equipment, training, and funding.
  • Reward Facilities
    • Use media connections to provide coverage for successful efforts. Positive publicity can mean increased business.
    • Visibly displayed awards or certificates may also improve business.

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What other Web sites related to pollution reduction for ICI boilers are available?

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