Focus On Air Division
Air Toxics Program
General Air Toxics Information


What are air toxics?

Toxic air pollutants, known as hazardous air pollutants (HAPs) are pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects. There are 187 regulated HAPs.*

Such pollutants include arsenic, asbestos, mercury, and benzene. The list of regulated HAPs is located in Appendix II and III of Title 129 - Nebraska Air Quality Regulations.

What has been done to reduce toxic air pollutants?

The Clean Air Act Amendments of 1970 required that the U.S. Environmental Protection Agency (EPA) develop standards to regulate emissions of toxic air pollutants, also known as HAPs. The standards regulate HAP emissions from new and existing sources on a pollutant-by-pollutant basis. This proved to be a difficult challenge for EPA to develop and promulgate these standards because they had to be risk-based and had to provide “an ample margin of safety.” EPA was continuously challenged on the basis that the “ample margin of safety” was either too strict or not strict enough. Due to these challenges, only seven HAP standards were promulgated in twenty years. These standards are referred to as National Emission Standards for Hazardous Air Pollutants (NESHAPs) and are found in Title 40 of the Code of Federal Regulations Part 61 (40 CFR Part 61).

A different approach was taken to regulate HAP emissions in the Clean Air Act Amendments of 1990. The 1990 amendments require a two-phase approach to regulating HAP emissions. The first phase consists of developing technology-based standards that require sources to meet specific emission limits that are based on emissions levels already being achieved by many similar sources in the country. The technology-based standards are referred to as Maximum Achievable Control Technology (MACT) standards. MACT standards are found in Title 40 of the Code of Federal Regulations Part 63 (40 CFR Part 63).

The second phase of HAP emission regulation applies a risk-based approach in which EPA will assess how well the technology-based standards have done in reducing the public health and environmental risks. If EPA finds that there are any significant remaining or residual health or environmental risks, they may implement additional standards. EPA has been assessing residual risk for many of the rules promulgated in the early 1990’s. For more information on those rules, visit EPA’s Air Toxics Web Site – Risk and Technology Review.*

Additionally, under EPA’s Urban Air Toxics Strategy, emission regulations are being developed to reduce emissions from smaller air toxic emission sources and mobile sources. Current information related to these rules can be found on EPA’s Air Toxics Web Site – Area Source Standards.*

How are the air toxic rules implemented in Nebraska?

The NDEQ Air Quality Division adopts, implements, and enforces the federal air toxic standards for much of Nebraska. The Omaha Air Quality Control and Lincoln-Lancaster County Health Department are responsible for the air quality programs in their respective areas.

The NDEQ will wait approximately one year after EPA finalizes a regulation prior to adopting the rule into the air quality regulations. However, it isn’t necessary to adopt all of the standards into Title 129. There may be standards promulgated that would not likely affect sources in NE. The standards found in 40 CFR Part 61 are found in Title 129 Chapter 23. Standards found in 40 CFR Part 63 are located in Title 129 Chapter 28.

In addition to the federal regulations, NDEQ has a state toxics rule requiring sources with a potential net emissions increase above 2.5 tons per year of a single hazardous air pollutant (HAP) or 10 tons per year of combined HAPs to install the best available control technology to reduce their emissions. These requirements are found in Title 129 Chapter 27.

Need Assistance?

If you have questions regarding the NDEQ Air Toxics Program, call (402) 471-2189.

NDEQ Resources

Air Toxics Resources

Air Toxics Notebook - Guide to NESHAPs

Air Toxics Publications, Forms and Applications

* This Page contains links to Non-NDEQ websites, these links will open in a New Tab or Window