Dougherty said the data problems came to Caltrans' attention in 2008. Subsequently, Wiles was transferred to an desk job. At that point, the Office of Inspector General, U.S. Dept. of Transportation and the Federal Highway Administration got involved in the investigation, said Dougherty. The OIG's investigation was based on an FHA draft report that was not available to the public.

In 2006 and 2007, Wiles, along with other technicians, inspected 13 concrete and rebar piles buried under San Francisco Bay. Wiles' test results for density were very different from the other technicians' findings. The Bee reported that Wiles' colleagues questioned the results of his gamma-gamma logging device because, before using it, he failed to test the device itself, which is mandatory.

Besides the peer-review panel, leaders of the state Senate and Assembly committees on transportation are planning hearings this month regarding the Bay Bridge's potential safety issues.

Members of the Seismic Safety Peer Review Panel are Dr. Frieder Seible, dean of the Jacobs School of Engineering at the University of California at San Diego; Dr. I.M. Idriss, an independent consulting geotechnical engineer and emeritus professor of civil engineering at the University of California at Davis; Dr. John Fisher, professor emeritus of civil engineering at Lehigh University and director emeritus of the Advanced Technology for Large Structural Systems' Engineering Research Center; and structural engineer Joseph Nicoletti, who served as the chairman of the Engineering and Design Advisory Panel for the Bay Bridge East Span replacement project. Nicoletti is also the chairman of the peer-review panel.

Caltrans spokesman Bart Ney was not sure when the panel's report would be made public.

"Best estimate is a couple months for the review panel to reach their conclusion," Ney said.