A senior Senate Republican is trying to determine how far the Food and Drug Administration took its alleged monitoring and retaliation against employees who raised safety concerns about some medical devices.

At issue is whether the agency monitored the personal e-mail accounts of nine of its employees who wrote President Barack Obama's transition team and members of Congress to express their safety concerns with radiological devices used to detect breast cancer and other diseases. Six current and former FDA employees filed a lawsuit last week against the agency that accused it of secretly monitoring their personal email accounts.

Sen. Charles Grassley (R-Iowa) wrote FDA Commissioner Dr. Margaret Hamburg (PDF) this week for details about the monitoring and the fate of the FDA employees who wrote the safety concerns.

Grassley said he previously wrote the agency on the issue in 2009 to explicitly remind officials there that federal law gives FDA employees the right to provide information to Congress.

“Still, even after that letter, the FDA appears to have persisted in a long campaign to punish a group of employees for talking to Congress,” Grassley wrote. “I'm pursuing this matter with the FDA to get answers and ensure that whistle-blowers aren't singled out and retaliated against for protected disclosures to Congress.”

The FDA engaged in extensive monitoring of the employees' private e-mail accounts, Grassley wrote, apparently to try to justify the agency's case for retaliation.

Grassley asked Hamburg to respond by Feb. 17.