Home › CFR › Title 25 › Part 57325 CFR Part 573 — Compliance and Enforcement§ 573.1— What is the purpose of this part?§ 573.2— When may a letter of concern be issued?§ 573.3— Notice of violation.§ 573.4— When may the Chair issue an order of temporary closure?§ 573.5— When does an enforcement action become final agency action?