US lawIllinoisRegulationsTitle 35 — ENVIRONMENTAL PROTECTIONCHAPTER I: POLLUTION CONTROL BOARDPart 301 — INTRODUCTION301.22135 Ill. Adm. Code 301.221Area of ConcernLast amended: 2023Year: 2026Length: 20 wordsOfficial source Section 301 Section 301.221 Area of Concern "Area of Concern" or "AOC" is an area specially designated for remediation efforts.Previous35 Ill. Adm. Code 301.220Next35 Ill. Adm. Code 301.225