(a) The Administrator shall issue a notice of noncompliance to the owner or operator of any source which he determines is in violation of applicable legal requirements and which is located in a State without an approved section 120 program.

(b) The Administrator shall send a notice of noncompliance to the owner or operator of any source located in a State with an approved section 120 program when he determines as provided in part 67 that the source is in violation of applicable legal requirements and the State has failed to send a notice of noncompliance to it, or has failed to pursue diligently any subsequent steps for the assessment or collection of the penalty.

(c) Failure of EPA or a State to issue a notice of noncompliance within 30 days after discovery of a violation shall not affect the obligation of a source owner or operator to pay a noncompliance penalty but shall affect the date from which the penalty is calculated. The penalty shall be calculated from the earliest date that the owner or operator of the source received a notice of noncompliance under this section, whether issued by EPA or the State.