(a) Necessary findings
After notice and opportunity for public comment have been provided in accordance with section 4804 of this title, the Secretary shall issue and publish an order if the Secretary finds, and sets forth in such order, that the issuance of such order and all terms and conditions thereof will assist in carrying out this chapter.

(b) Number of orders in effect at a time
Not more than one order may be in effect at a time.

(c) Effective date
An order shall become effective on a date that is not more than 90 days following the publication of such order.

(d) Terms and conditions
An order shall contain such terms and conditions as are required in sections 4806 through 4809 of this title and, except as provided in section 4810 of this title, no others.