Our objective was to determine whether the Postal Service properly issued security clearances to contractor personnel at Surface Transfer Centers (STC).

STCs are mail consolidation and re-distribution facilities that assist the Postal Service in maximizing the utilization of vehicles and their capacity to transport mail. The Postal Service operates 13 STCs, seven of which are managed solely by STC suppliers who, as of April 2021, employ over 1,000 contractor personnel. The contractor personnel are responsible for performing mail processing operations, with Postal Service personnel overseeing those operations for contract compliance.

The Postal Service is obligated to maintain the security of the mail and preserve the public’s trust. The security clearance process is designed to prevent ineligible or unsuitable applicants from having access to the mail, Postal Service assets, and facilities.

The U.S. Postal Inspection Service (Inspection Service) is responsible for reviewing requests for security clearances and determining if the security clearances should be granted. To assist in the process, STC contracts require suppliers to conduct certain background investigation steps, such as conducting a drug screening and local criminal background check. The STC supplier is also responsible for submitting the results of those steps and supporting documentation directly to the Inspection Service and retaining related documentation for the personnel they hire.

The Inspection Service notifies the STC suppliers when contractor personnel have been granted or denied a non-sensitive security clearance. STC suppliers must request a clearance prior to contractor personnel gaining access to mail. Generally, STC contractor personnel granted a non-sensitive clearance and working continuously on their assigned contract with no breaks do not require rescreening.


We found the security clearance process was not always followed for 130 of the 169 (77 percent) randomly selected STC contractor personnel. Postal Service management did not always ensure that STC suppliers requested or timely requested security clearances for contractor personnel. In addition, the Inspection Service conducted some security clearance investigations steps that are required to be completed by STC suppliers. Further, when STC suppliers did conduct the required security clearance investigation steps, they did not always retain documentation supporting the steps completed. Specifically, we found:

  • STC suppliers did not request security clearance investigations for eight of the 169 (5 percent) randomly selected STC contractor personnel we reviewed. Four of the eight STC contractors were still employed by the STC supplier during our audit and had access to the mail. During the audit, one of the four STC contractors received a security clearance.
  • Forty-three of the 169 (25 percent) randomly selected STC contractors did not have a security clearance requested timely by the STC supplier. Ten of the 43 requests occurred over one year after the contractor started working for the STC suppliers. For one contractor, the Inspection Service, during our audit, made an unfavorable determination and that contractor was subsequently terminated.
  • The Inspection Service granted clearances for 66 of the 169 randomly selected STC contractor personnel when applicable STC suppliers did not submit supporting documentation or certify completion of required security clearance investigation steps for which they were responsible. These documents included county criminal record checks. When the Inspection Service did not receive documentation of a county record check from the STC suppliers, the Inspection Service ordered the documentation through its own contractor.
  • STC suppliers that certified completion of required security clearance investigation steps did not always retain documentation supporting completion of those steps for 63 of 161 clearances conducted.

These conditions occurred for a variety of reasons:

  • STC contracts did not require STC suppliers to notify Postal Service officials when they hire new contractor personnel or to periodically report to Postal Service officials on the status of security clearance requests.
  • STC contracts required the suppliers to submit required documentation for security clearance requests directly to the Inspection Service. Postal Service contracting officials were not required to review the documents for completeness and adequacy prior to submission to the Inspection Service.
  • STC contract requirements were unclear related to maintaining clearance documentation. For example, although the contracts require that all information be held by the STC supplier, they also establish that the STC suppliers’ records should minimally contain only social security number, current address, date of birth, employee identification badge number, drug screening results, and the security clearance notification for contractor personnel. In addition, the STC contracts did not specify how long STC suppliers must retain contractor personnel records.

Without completed security clearances for all STC contractor personnel, the Postal Service was unable to verify whether contractor personnel were suitable to work under those contracts. In addition, a favorable security clearance based on unverified or incomplete background screening steps could place the safety and security of Postal Service and STC contractor personnel, mail, and Postal Service information at risk. Further, the Inspection Service incurred additional costs as a result of ordering criminal record checks for which STC suppliers were responsible.


We recommended management:

  • Remove access to the mail for the three contractor personnel currently working without a security clearance until they are granted a non-sensitive security clearance.
  • Update each STC contract to require STC suppliers to (1) notify Postal Service officials of new hires upon employment acceptance, (2) keep Postal Service officials apprised on the status of the security clearance requests for new hires, and (3) submit security clearance investigation documentation to Postal Service contracting personnel prior to submission to the Inspection Service.
  • Clarify language in STC contracts to specify which security clearance documents must be retained and the period of retention.

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