41 C.F.R. § 105-68.425 When do I check to see if a person is excluded or disqualified?
Title 41 - Public Contracts and Property Management
As an 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 agency approval of the lower tier participant is required; or (d) Approve a principal in connection with a lower tier transaction if agency approval of the principal is required.
Title 41: Public Contracts and Property Management
PART 105–68—GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT)
Subpart D—Responsibilities of GSA Officials Regarding Transactions
§ 105-68.425 When do I check to see if a person is excluded or disqualified?

