Section 112 of the federal Clean Air Act (CAA) contains requirements for the reduction of air toxics, also known as hazardous air pollutants (HAPs), from human sources. The CAA provides an initial list of 189 compounds, which U.S. EPA has modified to the current list of 187 regulated substances. Title 326 of the Indiana Administrative Code (326 IAC) contains Indiana’s rules for air pollution, including requirements specifically for the control of HAPs at 326 IAC 14 [PDF] (Emission Standards for Hazardous Air Pollutants) and 326 IAC 20 [PDF] (Hazardous Air Pollutants).
Indiana’s rules for HAPs often refer to and regulate specific industries or industrial processes based on U.S. EPA’s National Emissions Standards for Hazardous Air Pollutants (NESHAPs). If Indiana agrees to be responsible for enforcing a particular federal NESHAP (referred to as accepting delegation) then the state must adopt a rule to implement and enforce the federal regulation. IDEM currently has accepted delegation of 111 NESHAPs.
Additional state rules cover HAPs, as well. For example, portions of 326 IAC 11 [PDF] (Emission Limitations for Specific Types of Operations) place limits on certain HAPs emissions, specifically those from various types of incinerators. State rules at 326 IAC 2-2 [PDF] (Prevention of Significant Deterioration) and 326 IAC 2-3 [PDF] (New Source Review) regulate new sources or modifications of emission units that emit certain toxics, such as lead, beryllium, mercury, vinyl chloride, and fluorides.
In addition to rules that regulate emissions from various industrial sources, IDEM also has the authority to require sources to provide additional information about their emissions to the air as part of 326 IAC 2-6 [PDF] (Emissions Reporting). Specifically 326 IAC 2-6-5 allows IDEM to request additional emissions information to aid in completion of specific projects. This subsection of the rule is not often needed, but can be used to aid IDEM in conducting more detailed emissions analyses resulting from local or federal concerns or regulations.
More information about IDEM’s Air Pollution Control rules can be found on the IDEM Legal Counsel: Rulemaking page.