40 CFR 27.46: Compromise or settlement.

(a) Parties may make offers of compromise or settlement at any time.

(b) The reviewing official has the exclusive authority to compromise or settle a case under this part at any time after the date on which the reviewing official is permitted to issue a complaint and before the date on which the presiding officer issues an initial decision.

(c) The Environmental Appeals Board has exclusive authority to compromise or settle a case under this part at any time after the date on which the presiding officer issues an initial decision, except during the pendency of any review under § 27.42 or during the pendency of any action to collect penalties and assessments under § 27.43.

(d) The Attorney General has exclusive authority to compromise or settle a case under this part during the pendency of any review under § 27.42 or of any action to recover penalties and assessments under 31 U.S.C. 3806.

(e) The investigating official may recommend settlement terms to the reviewing official, the Environmental Appeals Board, or the Attorney General, as appropriate. The reviewing official may recommend settlement terms to the Environmental Appeals Board or the Attorney General, as appropriate.

(f) Any compromise or settlement must be in writing.