The Director shall prescribe regulations and shall carry out the provisions of this chapter so as to assure that the service of volunteers assigned, referred, or serving pursuant to grants, contracts, or agreements made under this chapter is limited to activities which would not otherwise be performed by employed workers or other volunteers (not including participants under this chapter and the National and Community Service Act of 1990 (
42 U.S.C.
12501 et seq.)), and which will not supplant the hiring of or result in the displacement of employed workers or other volunteers (not including participants under this chapter and the National and Community Service Act of 1990 (
42 U.S.C.
12501 et seq.)),, or impair existing contracts for service.