The director , pursuant to regulations prescribed by him or her, may authorize sales of pesticides to be made out of a registrant’s opened but properly labeled lot, container, or package. The director shall serve notice of the proposed action by depositing a copy of it in a United States post office, inclosed in a sealed envelope with postage prepaid and addressed to each registrant at his or her last address on file with the department. The director shall allow 15 days, during which time any protest may be filed.