WASHINGTON (Reuters) – The Food and Drug Administration said it is reviewing whether its secret monitoring of staff emails adequately protected whistleblowers, as the fallout from the surveillance operation expands.

Six current and former FDA scientists and doctors filed a lawsuit in January charging the agency tried to repress warnings about potential corruption in device reviews by retaliating against them for passing information to Congress and the media.

Over the weekend, the scandal grew when the New York Times revealed documents detailing the wide scale of the surveillance operation.

It reported that the FDA secretly captured thousands of emails the scientists sent privately to lawmakers, their aides, journalists and President Barack Obama.

The report further stoked anger from lawmakers who were already concerned about the surveillance.

Senator Chuck Grassley, a Republican from Iowa and an advocate for whistleblower protections, in January sent a letter to the FDA, asking about its monitoring program and how it ensures staff communication with Congress remains private.

The FDA’s response to Grassley’s request arrived on Friday.

“FDA is currently reviewing and evaluating its policies and practices to ensure that they are consistent with the law and Congress’s intent to provide a secure channel for protected disclosures,” Jeanne Ireland, the FDA’s assistant commissioner for legislation, said in a letter.

The Office of Special Counsel (OSC), an independent agency that protects federal whistleblowers, in February broadened an investigation into whether the FDA violated the law by keeping track of employee emails to Congress and the OSC. Such emails are supposed to remain confidential.

The OSC and the Office of Management and Budget also sent memos to all government agencies in June, warning them about the legal restrictions on monitoring employees’ emails. The memos suggest other agencies beyond the FDA may face similar issues in monitoring whistleblowers.

The FDA said on Monday it monitored emails only to ensure its staff were not sharing specific “trade secret” information about specific device companies, which is forbidden by law, and that it never stopped the whistleblowers from contacting lawmakers, journalists or government auditors.

“The only individuals whose email was being monitored were (five) FDA employees,” said Erica Jefferson, FDA spokeswoman.

“We did not impede or interfere in any way with any employees’ communication to members of Congress.”

But Grassley said the FDA must further explain its actions.

“The extent to which the FDA spied on employees’ personal email is shocking,” he said in an emailed statement on Monday.

“The FDA’s actions raise serious implications for the right of any agency employee to make protected disclosures about waste, fraud, abuse, mismanagement, or public safety to Congress or anyone else.”

(Reporting by Anna Yukhananov; Editing by Tim Dobbyn)