Most air permitting focuses on criteria pollutants. However, rules do exist which require large emitters of Hazardous Air Pollutants (HAPS) to obtain permits for those emissions. As a general rule, any facility that releases more than 10 tons of a single HAP or a total of 25 tons of all HAPs in a given year is required to obtain a permit. In addition, if there is a public complaint, IDEM may perform additional HAPs modeling as part of the permitting process, though the facility may not require a permit for those emissions.
The IDEM Air Permits page provides additional information about IDEM’s Air Permitting Process.