2 C.F.R. § 180.425

As a Federal agency official, you must check to see if a person is excluded or disqualified before you:

(a) Enter into a primary tier covered transaction;

(b) Approve a principal in a primary tier covered transaction;

(c) Approve a lower tier participant if your Federal agency's approval of the lower tier participant is required; or

(d) Approve a principal in connection with a lower tier transaction if your Federal agency's approval of the principal is required.