MONTPELIER, Vt. – A panel appointed by Vermont lawmakers to examine the reliability of Vermont Yankee said Tuesday that a change in corporate culture is needed if the 38-year-old nuclear power plant is to operate past its scheduled 2012 closing.

In a revised version of its March 2009 report, the Vermont Yankee Public Oversight Panel took up two issues stemming from developments since then — a leak of radioactive tritium that contaminated soil and groundwater around the Vernon power plant, and owner Entergy Corp.’s acknowledgment that its representatives misled Vermont lawmakers and regulators by saying the plant had no underground piping capable of carrying radionuclides.

The panel’s new conclusion: “Entergy cannot operate VY reliably for an additional 20 years unless it successfully re-establishes a corporate culture where its individual employees and the organization as a whole have a questioning attitude, and where adequate resources are consistently spent on nonsafety systems.”

The report called the misleading statements — which led to the disciplining of 11 Vermont Yankee employees — the result of an “organization-wide breakdown” but said that, as of 2008, they didn’t appear to have been part of a deliberate effort to deceive.

The panel also stood by its 2009 conclusion: With proper equipment maintenance, the plant could be safely operated past 2012.

The three-member panel was appointed to help Vermont lawmakers decide whether to permit Vermont Yankee to be re-licensed. It was asked to issue a supplemental report earlier this year after the controversy over the tritium leak and revelations about the existence of the underground piping.

Vermont is the only state in the nation that gives itself the authority to block a nuclear plant’s re-licensing.

In February, the state Senate voted 26-4 to reject Vermont Yankee’s re-licensing, but Entergy Corp. officials are hoping a changing roster at the Statehouse — legislative elections are Nov. 2 — could prompt a second vote with a different outcome.

Four lawmakers who released the new report at a Statehouse news conference Tuesday said they don’t expect a re-vote, but they didn’t rule it out either.

“For us to make a decision about the future of Vermont Yankee, it is necessary for us to get accurate information,” said House Speaker Shap Smith, D-Morristown. “It is necessary for us to be able to rely on the organization that is providing information. What this report shows is that we cannot do that here. And without the ability to rely on that entity to be forthright, it is unclear how we could allow it to continue to operate in such a difficult environment.”

Vermont Yankee spokesman Larry Smith said the plant would continue to press lawmakers to let it keep running.

“The public oversight panel report essentially reaffirms the central finding of the original 2009 report that, with caveats, Vermont Yankee can be operated reliably beyond 2012,” Smith said. “Vermont Yankee hopes that this conclusion is given due consideration as Vermont policymakers consider re-licensing in the coming months.”