45 C.F.R. § 180.80
(a) Material violations requiring a corrective action plan. CMS determines if a hospital's noncompliance with the requirements of this part constitutes material violation(s) requiring a corrective action plan. A material violation may include, but is not limited to, the following:
(c) Compliance with corrective action plan requests and corrective actions.
(2) A hospital's corrective action plan must specify elements including, but not limited to:
(d) Noncompliance with corrective action plan requests and requirements.