The Agency shall evaluate releases of contaminants whenever it determines that the extent of soil, soil gas, or groundwater contamination may extend beyond the boundary of the site where the release occurred. The Agency shall take appropriate actions in response to the release, which may include, but shall not be limited to, public notices, investigations, administrative orders under Sections 22.2d or 57.12(d) of this Act, and enforcement referrals. Except as provided in Section 25d-3 of this Act, for releases undergoing investigation or remediation under Agency oversight the Agency may determine that no further action is necessary to comply with this Section.