(a) If, after review of the engine manufacturer's application, request for certification, information obtained from any inspection, and any other information the Administrator may require, the Administrator determines that the test engine does not meet applicable standards and requirements, the Administrator will notify the manufacturer in writing, setting forth the basis for this determination.

(b) Notwithstanding the fact that engines described in the application may comply with all other requirements of this subpart, the Administrator may deny the issuance of or revoke a previously issued certificate of conformity if the Administrator finds any one of the following infractions to be substantial:

(1) The engine manufacturer submits false or incomplete information;

(2) The engine manufacturer denies an EPA enforcement officer or EPA authorized representative the opportunity to conduct authorized inspections;

(3) The engine manufacturer fails to supply requested information or amend its application to include all engines being produced;

(4) The engine manufacturer renders inaccurate any test data which it submits or otherwise circumvents the intent of the Act or this part; or

(5) The engine manufacturer denies an EPA enforcement officer or EPA authorized representative reasonable assistance (as defined in §90.506).

(c) If a manufacturer knowingly commits an infraction specified in paragraph (b)(1) or (b)(4) of this section or knowingly commits any fraudulent act which results in the issuance of a certificate of conformity, the Administrator may deem such certificate void ab initio.

(d) When the Administrator denies or revokes a certificate of conformity, the engine manufacturer will be provided a written determination. The manufacturer may request a hearing on the Administrator's decision.

(e) Any revocation of a certificate of conformity extends no further than to forbid the introduction into commerce of those engines previously covered by the certification which are still in the possession of the engine manufacturer, except in cases of such fraud or other misconduct that makes the certification void ab initio.