Ill. Admin. Code tit. 35, § 214.421
a) Section 214.162 notwithstanding, no person shall cause or allow the emission of sulfur dioxide into the atmosphere in any one hour period from any existing fuel combustion emission source at a steel mill located in the Chicago or St. Louis (Illinois) major metropolitan area burning any solid, liquid or gaseous fuel, or any combination thereof, to exceed the allowable emission rate determined by the following equation:
E = SSHS + SdHd + SRHR + SGHG
b) Symbols in the equation mean the following:
| E | = | allowable sulfur dioxide emission rate; |
| SS | = | solid fuel sulfur dioxide emission standard which is applicable; |
| Sd | = | distillate oil sulfur dioxide emission standard determined from the table in subsection (d); |
| SR | = | residual oil sulfur dioxide emission standard which is applicable; |
| SG | = | maximum by-product gas sulfur dioxide emissions which would result if the applicable by-product gas which was burned had been burned alone at any time during the 12 months preceding the latest operation, on or before March 28, 1983, of an emission source using any by-product gas; |
| HS | = | actual heat input from solid fuel; |
| Hd | = | actual heat input from distillate fuel oil; |
| HR | = | actual heat input from residual fuel oil; |
| HG | = | actual heat input from by-product gases, such as those produced from a blast furnace. |
c) That portion of the actual heat input that is derived:
d) Metric or English units may be used in the equation of subsection (a) as follows:
| Parameter | Metric | English |
| E | kg/hr | lbs/hr |
| SS, SR, SG | kg/MW-hr | lbs/mmBtu |
| Sd prior to January 1, 2017 | 0.46 kg/MW-hr | 0.3 lbs/mmBtu |
| Sd on and after January 1, 2017 | 0.0023 kg/MW-hr | 0.0015 lb/mmBtu |
| HS, Hd, HR, HG | MW | mmBtu |
(Source: Amended at 39 Ill. Reg. 16174, effective December 7, 2015)