What is Small
A small business as defined by Section 507 of the Clean Air Act is one that:
- is owned or operated by a person that employs 100 or fewer individuals,
 - is a small business concern as defined in the Small Business Act;
 - is not a major stationary source;
 - does not emit 50 tons or more per year of any regulated pollutant; and
 - emits less than 75 tons per year of all regulated pollutants.
 
... with certain exceptions of course.