No action to effect compliance by any other means authorized by law is to be taken until -
(a) The Director has determined that compliance cannot be secured by voluntary means;
(b) The recipient or other person has been notified by the Director, in writing, that it has been found in formal noncompliance and that it has 10 days before formal enforcement proceedings begin in which to enter into a written voluntary compliance agreement.
(c) The expiration of at least ten (10) days from the mailing of the notice to the recipient or other person.