(a) Refusal. At any time that the Administrator determines that an experimental use permit is not justified, or that the issuance of such a permit would cause unreasonable adverse effects on the environment, or that for any other reason provided for under the law a permit shall not be issued, he shall notify the applicant in writing.

(b) Revocation. The Administrator may revoke an experimental use permit if he finds that its terms or conditions are being violated or that its terms or conditions are inadequate to avoid unreasonable adverse effects on the environment, or if new evidence is obtained which demonstrates that the tolerance will be inadequate to protect the public health, or for failure to meet any other provision of this part 172. The Administrator will notify the permittee in writing of such revocation. The permittee shall notify all participants of such revocation as soon as possible after he receives notice of revocation. The revocation of a permit shall not preclude the Administrator from initiating civil or criminal sanctions for the violations of the permit conditions or otherwise as authorized by law.

(c) Hearing. In the event that an applicant for an experimental use permit wishes to contest the refusal to issue an experimental use permit, or an experimental use permittee wishes to contest the revocation of any such permit, he shall, within twenty days after receipt of notice of such refusal or revocation, file with the Administrator a written request for an opportunity to confer with the Administrator or his designee. Within twenty days after such conference, the applicant or permittee will be notified of the Administrator's final decision.