The amendment, sponsored by Senate Armed Services Committee Chairman Carl Levin (D-Mich.), also requires contractors to buy parts from trusted suppliers as determined by the Defense Department. Contractors also could make purchases from original manufacturers and their authorized dealers.
The Pentagon would also compile a list of untrusted suppliers.
The House passed its version of the defense authorization bill in May by a 322-96 vote. The House and Senate will convene a conference committee, consisting of lawmakers from both chambers, to resolve differences in their respective versions and then will send the compromise legislation to President Obama.