20 U.S. Code § 46a. Employment of aliens by Secretary

The Secretary of the Smithsonian Institution, subject to adequate security and other investigations as he may determine to be appropriate, and subject further to a prior determination by him that no qualified United States citizen is available for the particular position involved, is authorized to employ and compensate aliens in a scientific or technical capacity at authorized rates of compensation without regard to statutory provisions prohibiting payment of compensation to aliens.

(Pub. L. 88–549, Aug. 31, 1964, 78 Stat. 754.)