Audit, Compliance and Risk Blog

After more than 30 years EPA defines a new Hazardous Air Pollutant

Posted by Jon Elliott on Mon, Jan 17, 2022


Since 1990, the Clean Air Act (CAA) has defined a list of Hazardous Air Pollutants (HAPs), requiring the U.S. Environmental Protection Agency (EPA) to set emissions standards for many sources of these pollutants. HAPs include heavy metals, organics, and other airborne pollutants that are not otherwise regulated as “criteria” air pollutants (such as carbon monoxide, particulate matter, and ground level ozone). The 1990 CAA Amendments included a list of 189 HAPs (later corrected to 188), and empowered EPA to modify the list. In the intervening decades, EPA conducted rulemakings and deleted four initially-listed HAPs, but until 2022 had never added a new HAP. However, EPA has now added 1-bromopropane (1-BP) as a new HAP, effective February 4, 2022.

What is 1-BP?

The US federal Agency for Toxic Substances and Disease Registry (ATSDR) notes that 1-BP is a colorless liquid originally used in the production of pesticides, flavors and fragrances, pharmaceuticals, and other chemicals. It is currently used as a solvent in the adhesives, dry cleaning, vapor degreasing, and electronic and metal cleaning industries. Its solvent uses include both in solvent cleaning machines and as an applied solvent (e.g., wipe cleaning). In addition, EPA notes 1-BP uses reported in the manufacturing process as well as the final cleaning of metal and plastic rods and tubes. 1-BP production has increased over the last 10 years due to its use as a replacement for other more harmful substances.

ATSDR notes that 1-BP may have neurotoxic effects (brain and nerves). Repeated exposure to low levels in workplace air has been associated with minor effects, such as headache, decreased sensation in the fingers and toes, and a drunk-like feeling.

What are the implications of HAP listing?

EPA regulates HAPs through several programs applicable in different situations:

  • regulation of stationary sources (I summarized these HERE and HERE)

 - “major” sources (including application of National Emissions Standards for Hazardous Air Pollutants (NESHAPs)), based on emissions of individual HAPs and on aggregate emissions of all HAPs

 - “area” (minor) sources, including general requirements and EPA’s Urban Air Toxics program

  • mobile sources, primarily through regulation of vehicle emissions

  • indoor air quality programs, primarily through cooperation with other agencies regulating building materials and construction (although EPA has authority under CAA, the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and the Toxic Substances Control Act (TSCA) in some situations)

Readers should note that the new listing of 1-BP does not include any regulatory standards. However, EPA’s informational materials note that facilities will need to consider whether 1-BP emissions lead a facility to be a major source of HAPs, based on 1-BP emissions or on aggregate emissions including 1-BP.

What happens next?

EPA requires facilities to identify 1-BP emissions and consider their regulatory implications effective February 4, 2022. If inclusion of 1-BP results in a facility’s potential to emit all HAPs sufficient to qualify as a major source, the facility must either undertake binding activities to reduce emission below major source totals (as I discussed in the note linked above) or incorporate these emissions into its permit. EPA also states that it will undertake additional rulemakings, which should lead to a NESHAP for 1-BP.

Self-Assessment Checklist

Do any of the organization’s present or planned activities emit 1-BP?

  • At a facility regulated as a “major source” of HAPs, or which will qualify if 1-BP emissions are included?

  • At a facility regulated as an “area source” of HAPs?

Where can I go for more information?

Information about 1-BP and other HAPs is available from the following Internet sources:

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About the Author

Jon Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 30 years. 

Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).

Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).

You may contact Mr. Elliott directly at:

Tags: HAPs, Clean Air Act