40 CFR §63.211

1. (a)You are subject to this subpart if you own or operate a PVC plant, as defined in 40 CFR 61.61(c) of this chapter, that is a major source of hazardous air pollutants (HAP) emissions or that is located at, or is part of, a major source of HAP emissions.
2. (b)You are a major source of HAP emissions if you own or operate a plant site that emits or has the potential to emit any single HAP at a rate of 10 tons (9.07 megagrams) or more per year or any combination of HAP at a rate of 25 tons (22.68 megagrams) or more per year.