22 U.S.C. § 4112
Employees represented
The employees of the Department shall constitute a single and separate worldwide bargaining unit, from which there shall be excluded—
(1)
employees engaged in personnel work in other than a purely clerical capacity; and
(2)
employees engaged in criminal or national security investigations or who audit the work of individuals to insure that their functions are discharged honestly and with integrity.
( Pub. L. 96–465, title I, § 1012 , Oct. 17, 1980 , 94 Stat. 2135 .)