An Applicability Determination is the first step in determining whether or not you are applicable to a regulation.
This means that your emission-creating activity would be subject to compliance authority, monitoring or rule interpretations.
It is important to first look what has been ruled in the past in order to see if the rules apply to a similar practice.
Applicability Determinations Index
Region 10 Section 112(l) Federal Register- Air Toxics
National EPA Federal Register for all current rules.
Applicability Determinations by State