40 C.F.R. § 239.9 Intervention in civil enforcement proceedings.
Title 40 - Protection of Environment
Any state seeking approval must provide for intervention in the state civil enforcement process by providing either: (a) Authority that allows intervention, as a right, in any civil action to obtain remedies specified in §239.8 by any citizen having an interest that is or may be adversely affected; or, (b) Assurance by the appropriate state agency that: (1) It will provide notice and opportunity for public involvement in all proposed settlements of civil enforcement actions (except where immediate action is necessary to adequately protect human health and the environment); and, (2) It will investigate and provide responses to citizen complaints about violations; and, (3) It will not oppose citizen intervention when permissive intervention is allowed by statute, rule, or regulation.
Title 40: Protection of Environment
PART 239—REQUIREMENTS FOR STATE PERMIT PROGRAM DETERMINATION OF ADEQUACY
Subpart C—Requirements for Adequate Permit Programs
§ 239.9 Intervention in civil enforcement proceedings.