(a)  The head of each Executive agency shall, in a manner consistent with guidelines prescribed under subsection (b) of this section and applicable provisions of law, establish appropriate prevention, treatment, and rehabilitation programs and services for drug abuse and alcohol abuse for employees in or under such agency.

(b)  The Office of Personnel Management shall, after such consultations as the Office considers appropriate, prescribe guidelines for programs and services under this section.

(c)  The Secretary of Health and Human Services, on request of the head of an Executive agency, shall review any program or service provided under this section and shall submit comments and recommendations to the head of the agency concerned.