### Question
How does the law define major source?


### Answer
Under *42 U.S.C. § 7412*, **major source** is defined as:

> any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants

#### Citation:
  - *42 U.S.C. § 7412*
  - Heading: **CHAPTER 83-ENERGY EXTENSION SERVICE > SUBCHAPTER I-PROGRAMS AND ACTIVITIES > Part A-Air Quality and Emission Limitations**

