The Administrator initiates all rulemaking proceedings on his own motion by publishing an advance notice of proposed rulemaking or a notice of proposed rulemaking in the Federal Register. However, he may consider the recommendations of interested persons or other agencies of the United States. A separate docket is established and maintained for each rulemaking proceeding. Each rulemaking proceeding shall be completed not later than 12 months after the initial notice in that proceeding is published in the Federal Register. However, if it was initiated as the result of the granting of a rulemaking petition, the rulemaking proceeding shall be completed not later than 12 months after the petition was filed as prescribed in §§211.7 and 211.9.