Ill. Admin. Code tit. 35 § 270.407
A request to exceed the standards or limitations of Subchapter c of Chapter I of the Board's Air Pollution regulations (35 Ill. Adm. Code 212 et seq.) during startup of an emission unit, if desired, must be contained in the CAAPP application and shall include at a minimum a description of the startup procedure, the duration and frequency of such startups, the types and quantities of emissions during startup and the applicant's efforts to minimize any such startup emissions, duration of individual startups and frequency of startups, and all calculations used to determine the above information. In no event shall permission be given to operate during startup where such startup would result in an exceedance of the ambient air quality standard. The Agency may grant permission to operate during startup in accordance with 35 Ill. Adm. Code 201.262.
Ill. Admin. Code tit. 35, § 270.407