A metallurgist in the US state of Washington has pleaded guilty to fraud after she spent decades faking the results of strength tests on steel that was being used to make Navy submarines.
Prosecutors say Elaine Marie Thomas, 67, gave false positive readings for strength and toughness tests in at least 240 cases between 1985 and 2017.
Authorities did not disclose which vessels were affected.
But there was no indication that any submarine hulls had failed.
Ms Thomas, of Auburn, Washington, was the director of metallurgy at a foundry in Tacoma that supplied steel castings used by Navy contractors to make submarine hulls, the US Attorney’s Office for the Western District of Washington said in a statement.
The foundry was acquired by the manufacturer Bradken in 2008, according to the indictment. There was no evidence that the company’s management was aware of the fraud until May 2017. At that time, prosecutors say, a lab employee found out that test cards had been altered and that other discrepancies existed in the records.