- a) The Agency must determine the need for additional health advice appropriate to site-specific conditions when mixtures of chemical substances are detected and two or more of the chemical substances are similar-acting in their toxic or harmful physiological effect on the same specific organ or organ system.
- b) If mixtures of similar-acting chemical substances are present, the procedure for evaluating the mixture of the substances is specified in Appendices A, B, and C.
(Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025)