Emissions Limits:
Stericycle Inc.

Two types of pollutants are emitted by Stericycle: criteria pollutants and hazardous air pollutants (HAPS). The process of determining emission limits is slightly different for each type.

Criteria pollutants are six common air pollutants found all over the country. They are:

  • Carbon Monoxide (CO)
  • Lead (pb)
  • Nitrogen Dioxide (NOx)
  • Ozone
  • Particulate Matter (PM)
  • Sulfur Dioxide (SO2)

They are called criteria pollutants because they are regulated under human health-based and/or environmentally-based criteria that set permissible emission levels. Limits based on human health are primary standards. Limits intended to prevent environmental and property damage are secondary standards.

Areas that fail to meet the health-based National Ambient Air Quality Standards (NAAQS) for one or more of these criteria pollutants are subject to a variety of requirements to ensure air quality is restored to levels protective of public and environmental health.

Hazardous air pollutants are a class of chemicals specifically listed in the Clean Air Act (CAA) that can cause serious health and environmental hazards. The National Emission Standards for Hazardous Air Pollutants (NESHAPs) are stationary source standards for hazardous air pollutants. The 1990 CAA Amendments significantly expanded EPA’s authority to regulate hazardous air pollutants, with Section 112 of the Clean Air Act listing 187 hazardous air pollutants regulated by source category. The CAA does not set maximum concentration levels in the air for HAPs, but NESHAP standards require application of technology based emissions standards known as Maximum Achievable Control Technology (MACT). All relevant Utah facilities must comply with these federal hazardous air pollutant standards.

In addition to the federal technology standards, Utah evaluates hazardous pollutant emissions against toxic screening levels to protect the public living near the facility. To establish emission limits, DAQ uses Threshold Limit Values established by the American Conference of Government Industrial Hygienists. The Threshold Limit Values are based on the best science and are designed to protect the health of a worker who is spending eight hours a day at a facility over a normal career. When there is an adjacent neighborhood, DAQ takes into account other factors, including:

  • residents potentially spend more time at home than workers do at work
  • the ages of residents can range from infant to elderly
  • some residents may have health challenges and could be more susceptible to the effects of HAPs than a healthy adult

Emission Limits

The Utah State Plan (306 KB) establishes emission limits for HMWIs. These limits can be found in Tables 4A and 4B on pages 19-22 of the Plan.

The Plan includes compliance, performance testing, and monitoring requirements to ensure these limits are met. It sets maximum and minimum operating parameters and minimum frequency for data measurement and data recording. Stericycle is required to use EPA Reference Methods for its emissions testing.

EPA issued National Stack Testing Guidance to address issues associated with the conduct of stack tests. Stack test data is used to estimate the emissions inventory at Stericycle. Stericycle is currently the only registered HMIWI facility in Utah.


Sources include the Environmental Protection Agency and the Utah State Plan for HMIWIs.

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