The Administrator of the Environmental Protection Agency (hereinafter, the "Agency") may accept (notwithstanding sections 3302 and 1301 of title 31) diesel emissions reduction Supplemental Environmental Projects if the projects, as part of a settlement of any alleged violations of environmental law—

(1) protect human health or the environment;

(2) are related to the underlying alleged violations;

(3) do not constitute activities that the defendant would otherwise be legally required to perform; and

(4) do not provide funds for the staff of the Agency or for contractors to carry out the Agency's internal operations.