40 CFR 209.7: Effective date of order in complaint.

(a) The order in the complaint is effective and binding on respondent 20 days after service of the complaint, unless respondent requests a hearing pursuant to § 209.6. If the respondent does not request a hearing, the order is then a final order of the Agency.

(b) Respondent may file a motion with the complainant to vacate the final order, reopen the proceedings and request a hearing after the order is effective. This motion must be filed within twenty (20) days after the effective date of the order. The motion shall state the reasons respondent failed to file a timely answer, and provide the information required by § 209.6(b). The Administrator may, in his or her discretion and for good cause shown, grant the motion.