The Administrator, the Secretary of the Army, and the Secretary of Energy, respectively, are authorized to appoint, subject to the civil-service laws, such officers and employees as may be necessary to carry out the purposes of this chapter, the appointment of whom is not otherwise provided for, and to fix their compensation in accordance with chapter
51 and subchapter
III of chapter
53 of title
5. The Administrator may employ laborers, mechanics, and workmen in connection with construction work or the operation and maintenance of electrical facilities (hereinafter called “laborers, mechanics, and workmen”), subject to the civil-service laws. The Administrator is further authorized to employ physicians, under agreement and without regard to civil-service laws or regulations, to make physical examinations of employees or prospective employees who are or may become laborers, mechanics, and workmen. The Administrator, the Secretary of the Army, and the Secretary of Energy, respectively, are also authorized to appoint, without regard to the civil-service laws, such experts as may be necessary for carrying out the functions entrusted to them under this chapter.