WASHINGTON — A debate over how to balance government openness against the need to protect information vital to national security has reopened on Capitol Hill in the wake of a 2011 Supreme Court decision.

In the middle of “Sunshine Week,” designed to promote government transparency, the Senate Judiciary Committee heard arguments Tuesday on amending the Freedom of Information Act to safeguard critical infrastructure information. In March 2011, the Supreme Court removed the right of government agencies to deny FOIA requests for “predominately internal materials” that would “significantly risk circumvention of agency regulations or statutes.” It came in response to the Navy withholding maps of a Washington state base that would have revealed key information about infrastructure and explosives. Glen Milner requested the information because he wanted to know if his family would be vulnerable in the event of an attack.

The decision overturned more than three decades of FOIA precedents, said Miriam Nesbit, director of the Office of Government Information Services, which bills itself as the federal government’s ombudsman. While it may be possible for agencies to use other exemptions in FOIA, an amendment to the law is needed to ensure the protection of vital government infrastructure, she said.

“Requesters as well as agencies have indicated to us the need for changes to FOIA post-Milner,” Nesbit said. “This effort could focus on finding a generic approach available across government that takes into account both the concerns of agencies and requesters to address a subset of sensitive information.”

Melanie Ann Pustay, director of the Justice Department’sOffice of Information Policy, said it is time to “go beyond a piecemeal approach and go on to a real solution for the problem.”

While many government experts agree that changes to FOIA are needed to prevent secret information from getting into the wrong hands, Judiciary Committee Chairman Patrick Leahy said that any amendment should be worded carefully.

“As Congress considers other proposed legislative exemptions to FOIA for critical infrastructure information, I intend to work with members on both sides of the aisle to ensure that the public’s interest in accessing essential health and safety information is protected,” Leahy, D-Vt., said.

Others say national security needs mean the government must protect its vital information.

Paul Rosenzweig, professorial lecturer at The George Washington University, said a blanket FOIA exemption is essential to ensure U.S. cybersecurity. He said “cybercrime is epidemic and growing,” and that certain pieces of government information are too sensitive to disclose.

“Identifying publicly which cyber threats are known risks use of that information by terrorists and, in turn, draws a roadmap of which threats are not known,” Rosenzweig said. “Thus, complete transparency will defeat the very purpose of disclosure and may even make us less secure.”

But Jerry Ensminger, a retired Marine, told the committee it should encourage government transparency and only amend the Act narrowly. He said his young daughter died of leukemia in the 1980s, which he later learned was due to contaminated drinking water at Camp Lejune, N.C. Ensminger said he was blocked from getting that information because it dealt with “critical infrastructure information.”

“The last thing we need is more secrecy disguised as a concern for the security of critical infrastructure,” Ensminger said. “Any exemption must be very narrowly defined.”