2 U.S. Code § 1535 - Least burdensome option or explanation required
(a) In general
Except as provided in subsection (b) of this section, before promulgating any rule for which a written statement is required under section 1532 of this title, the agency shall identify and consider a reasonable number of regulatory alternatives and from those alternatives select the least costly, most cost-effective or least burdensome alternative that achieves the objectives of the rule, for—
(1) State, local, and tribal governments, in the case of a rule containing a Federal intergovernmental mandate; and
The provisions of subsection (a) of this section shall apply unless—
(1) the head of the affected agency publishes with the final rule an explanation of why the least costly, most cost-effective or least burdensome method of achieving the objectives of the rule was not adopted; or
(c) OMB certification
No later than 1 year after March 22, 1995, the Director of the Office of Management and Budget shall certify to Congress, with a written explanation, agency compliance with this section and include in that certification agencies and rulemakings that fail to adequately comply with this section.