As provided by section 4 of the Act and under provisions of sections 4 and 5 of the Walsh-Healey Public Contracts Act (49 Stat. 2036, 41 U.S.C. 38,39,which,the,to,issue,make,and. The Secretary is also authorized to make reasonable limitations and to make rules and regulations allowing reasonable variations, tolerances, and exemptions to and from provisions of the Act (except section 10), but only in special circumstances where it is determined that such action is necessary and proper in the public interest or to avoid serious impairment of the conduct of Government business and is in accord with the remedial purposes of the Act to protect prevailing labor standards. The authority and enforcement powers of the Secretary under the Act are coextensive with the authority and powers under the Walsh-Healey Act. Curtiss Wright Corp. v. McLucas 364 F. Supp. 750, 769 (D NJ 1973).