When the Postal Service finds a claim for damage to persons or property resulting from the operation of the Postal Service to be a proper charge against the United States, and it is not cognizable under section 2672 of title 28, it may adjust and settle the claim.
39 U.S. Code § 2603. Settlement of claims for damages caused by the Postal Service
Charge Against Postal Revenues for Settlement of Claims for Damages and for Losses Resulting From Unavoidable Casualty
“That hereafter settlement of claims, pursuant to law, current and prior fiscal years, for damages, and for losses resulting from unavoidable casualty shall be paid from postal revenues.”