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Guardian Industries Corp. Clean Air Act Settlement

(Washington, DC – September 29, 2015) EPA and the U.S. Department of Justice announced that Michigan-based Guardian Industries Corp., a manufacturer of flat glass used in automobiles and buildings, which is also known as float glass, has agreed to install pollution control equipment to reduce emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), sulfuric acid mist (H2SO4), and particulate matter (PM) by nearly 7,500 tons per year, implement a $150,000 mitigation project, and pay a $312,000 penalty to resolve alleged Clean Air Act violations at the company’s glass manufacturing plants.

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Overview of Company

Guardian produces float or flat glass used in automobiles and buildings. The company owns seven flat glass manufacturing facilities in seven states. The company is headquartered in Auburn Hills, Michigan. The settlement covers all of the company’s flat glass manufacturing facilities in the U.S., which are located in the following areas:

  • Kingsburg, California
  • DeWitt, Iowa
  • Carleton, Michigan
  • Geneva, New York
  • Floreffe, Pennsylvania
  • Richburg, South Carolina
  • Corsicana, Texas

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The complaint alleges that Guardian constructed or made modifications to furnaces at the company’s facilities, resulting in increased emissions of nitrogen oxide (NOx), sulfur dioxide (SO2), sulfuric acid mist (H2SO4), and particulate matter (PM), without first obtaining pre-construction permits and installing required pollution control equipment, in violation of:

  • The Clean Air Act (CAA) Prevention of Significant Deterioration, and Title V permitting requirement provisions, 42 U.S.C. §§ 7470-7492 and 7661-7661f.
  • The State Implementation Plans (SIPs) in each of the states where the facilities are located, 42 U.S.C §7410.

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Injunctive Relief

Guardian will spend an estimated $70.6 million on state-of-the-art controls to reduce emissions of NOX, SO2, H2SO4, and PM and to install continuous emissions monitors. Guardian made an independent business decision to close the Floreffe, Pennsylvania facility.

NOx Controls (all operating furnaces will have controls)

  • Selective catalytic reduction designed to reduce NOX emissions by 90 percent.
  • All of the company’s operating furnaces will be subject to an 80 percent removal efficiency limit.

SO2 and H2SO4 Controls (all operating furnaces will have controls)

  • Dry scrubber systems.
  • All of the company’s operating furnaces will be subject to SO2 emission limits of 1.20 pounds per ton of glass pulled.
  • All of the company’s operating furnaces will be subject to H2SO4 limits of 1.6 pounds of H2SO4 per hour.

PM Controls (all operating furnaces will have controls)

  • Particulate devices.
  • All of the company’s operating furnaces will be subject to PM emission limits of 0.45 pounds of PM per ton of glass pulled.


  • Guardian will install and operate NOX and SO2 continuous emissions monitoring systems
    on all of its operating float glass furnaces. The NOX monitoring system will monitor both the inlet and outlet to determine the NOX removal efficiency.

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Pollutant Reductions

This settlement will result in the following estimated emissions reductions once all emissions controls and emissions-reduction practices have been implemented:

  • Nitrogen Oxides: more than 6,400 tons per year (tpy)
  • Sulfur Dioxide: more than 550 tpy
  • Sulfuric Acid Mist: more than 200 tpy
  • Particulate Matter: more than 140 tpy

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Health Effects and Environmental Benefits

NOx, SO2, H2SO4, and PM all have adverse effects on human health and the environment, as discussed below:

  • Nitrogen Oxides – NOx can cause or contribute to a variety of health problems and adverse environmental impacts such as visual impairment, water quality deterioration, ground-level ozone, acid rain, and global warming. Affected populations include children, people with lung diseases such as asthma, and people who work or exercise outside.
  • Sulfur Dioxide – High concentrations of SO2 can affect breathing and may aggravate existing respiratory and cardiovascular disease. Sensitive populations include asthmatics, individuals with bronchitis or emphysema, children, and the elderly. SO2 is also a primary contributor to acid deposition and visibility impairment.
  • Sulfuric Acid Mist – H2SO4 is a corrosive chemical and can severely burn the skin and eyes. It may cause third degree burns and blindness on contact. Exposure to sulfuric acid mist can irritate the eyes, nose, throat and lungs, and at higher levels can cause a buildup of fluid in the lungs (pulmonary edema). Asthmatics are particularly sensitive to the pulmonary irritation. Repeated exposures may cause permanent damage to the lungs and teeth.
  • Particulate Matter – Particulate matter, especially the fine particles, can travel deep into a person’s lungs, causing coughing, decreased lung function, chronic bronchitis, and even death. Sensitive populations include the elderly, children, and people with pre-existing heart or lung disease. Particulate matter also contributes to haze which can affect visibility, and causes outdoor monuments and structures to become dirty.

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Environmental Mitigation

Guardian will spend an additional $150,000 to mitigate emissions at the Kingsburg, California plant through the San Joaquin Valley Unified Air Pollution Control District’s Clean Burn Program to replace high emitting wood burning appliance with lower-emitting appliances. 

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Civil Penalty

Guardian will pay a $312,000 civil penalty. $156,000 of the penalty will be paid to the United States; $78,000 will be paid to the state of Iowa; and $78,000 will be paid to the state of New York.

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Comment Period

The proposed settlement, lodged in the U.S. District Court for the Eastern District of Michigan,  is subject to a 30-day public comment period and final court approval. Information on submitting comments is available at the Department of Justice website.

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Katie McClintock
U. S. Environmental Protection Agency
(206) 553-2143 

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