The FBI has requested all documents relating to the Bay Bridge project from Pile Drivers Local 34, according to the union's attorney Sandra Benson.
The union represents Bay Bridge welders, who work for prime contractor KFM Joint Venture.
The FBI subpoenaed "anything that Local 34 has relating to the KFM job at the bridge," Benson said Monday, adding that the union is fully cooperating with the investigation. "And we are compiling documents as we speak," she said.
The FBI's San Francisco office declined further comment Monday about its ongoing probe into allegations by bridge welders that they were pressured into concealing bad weldson the $1.5 billion project.
KFM and Caltrans have consistently and vehemently denied the allegations. They have maintained that the bridge is safe and said they are fully cooperating with the FBI.
Laid-off welder Gustave Link said he first called the FBI's hotline in February to complain about the activities of his union. Three other welders, also interviewed by the FBI, reconfirmed that account Monday but said the attention of the Bureau's investigators appeared to be fixed on the quality of welds in the 160 steel piles supporting the replacement bridge.
There were no indications Monday that the FBI probe had widened or shifted focus.
Local 34 attorney Benson said she is unaware of any investigation of the union.
"I don't know why they would be," she said.
The documents that the union is compiling for the federal investigation contain nothing to support the welder allegations, Benson said.
"The union finds it hard to believe that it could be true," Benson said, adding that union officials knew nothing of the welders' accusations prior to last week. "No one ever said to the union, 'Oh, there are defective welds out there and all these people are turning a blind eye to it.'"
Benson said there are many welders, also members of Local 34, who have vouched for the quality of the welds.
The Inspector General of the U.S. Department of Labor is also investigating the Bay Bridge welding allegations. That office is one of at least 10 that has been asked to get to the bottom of the allegations.
Federal Highway Administration investigators arrived on Monday to begin assessing how to inspect the welds in the remaining four foundations that have not yet been buried in concrete.