A prior section 523 of act July 1, 1944, was renumbered section
544 by section 611(2) of
Pub. L. 100–77 and is classified to section
290dd–3 of this title.
1990—
Pub. L. 101–645 amended section generally, substituting present provisions for provisions which related to: in subsec. (a), general requirements; and in subsec. (b), determination of amount of non-Federal contribution.