Section 111(b) of Pub. L. 101–235 provided that: “The amendment made by subsection (a) [enacting this section] shall apply only with respect to—

“(1) violations referred to in the amendment that occur on or after the effective date of this section [Dec. 15, 1989]; and

“(2) in the case of a continuing violation (as determined by the Secretary of Housing and Urban Development), any portion of violation referred to in the amendment that occurs on or after such date.”