42 USC 215 - Detail of Service personnel

(a) Other Government departments 
The Secretary is authorized, upon the request of the head of an executive department, to detail officers or employees of the Service to such department for duty as agreed upon by the Secretary and the head of such department in order to cooperate in, or conduct work related to, the functions of such department or of the Service. When officers or employees are so detailed their salaries and allowances may be paid from working funds established as provided by law or may be paid by the Service from applicable appropriations and reimbursement may be made as agreed upon by the Secretary and the head of the executive department concerned. Officers detailed for duty with the Army, Air Force, Navy, or Coast Guard shall be subject to the laws for the government of the service to which detailed.
(b) State health or mental health authorities 
Upon the request of any State health authority or, in the case of work relating to mental health, any State mental health authority, personnel of the Service may be detailed by the Surgeon General for the purpose of assisting such State or a political subdivision thereof in work related to the functions of the Service.
(c) Congressional committees and nonprofit">nonprofit educational, research, or other institutions engaged in health activities for special studies and dissemination of information 
The Surgeon General may detail personnel of the Service to any appropriate committee of the Congress or to nonprofit">nonprofit educational, research[1] or other institutions engaged in health activities for special studies of scientific problems and for the dissemination of information relating to public health.
(d) Availability of funds; reimbursement by State; detailed services deemed service for computation of pay, promotion, etc. 
Personnel detailed under subsections (b) and (c) of this section shall be paid from applicable appropriations of the Service, except that, in accordance with regulations such personnel may be placed on leave without pay and paid by the State, subdivision, or institution to which they are detailed. In the case of detail of personnel under subsections (b) or (c) of this section to be paid from applicable Service appropriations, the Secretary may condition such detail on an agreement by the State, subdivision, or institution concerned that such State, subdivision, or institution concerned shall reimburse the United States for the amount of such payments made by the Service. The services of personnel while detailed pursuant to this section shall be considered as having been performed in the Service for purposes of the computation of basic pay, promotion, retirement, compensation for injury or death, and the benefits provided by section 213 of this title.
(e) Commissioned Corps officers; urgent or emergency public health care needs 
Except with respect to the United States Coast Guard and the Department of Defense, and except as provided in agreements negotiated with officials at agencies where officers of the Commissioned Corps may be assigned, the Secretary shall have the sole authority to deploy any Commissioned Corps officer assigned under this section to an entity outside of the Department of Health and Human Services for service under the Secretarys direction in response to an urgent or emergency public health care need (as defined in section 204a (a)(5) of this title).
[1] So in original. Probably should be followed by a comma.