Witness fees and allowances
For the purpose of this section, “agency” has the meaning given it by section 5721 of this title.
A witness is entitled to the fees and allowances allowed by statute for witnesses in the courts of the United States when—
he is subpenaed under section 304(a) of this title; or
he is subpenaed to and appears at a hearing before an agency authorized by law to hold hearings and subpena witnesses to attend the hearings.
(Pub. L. 89–554, Sept. 6, 1966, 80 Stat. 381.)