The Nuclear Regulatory Commission is refusing to release an unredacted version of its safety evaluation reports on Yucca Mountain, leaving the conclusions unknown to the public.

The agency notified Heritage that it had rejected an appeal under the Freedom of Information Act. The NRC’s decision comes eight months after Heritage first requested volumes II and III of the Yucca report in October. The NRC released more than 1,400 pages in February, but redacted the conclusions. Heritage appealed in March. (Full text of the letter is below.)

The NRC’s reports on Yucca have emerged as a contentious issue on Capitol Hill. Lawmakers have charged that the Obama administration ignored scientific information in a quest to halt the nuclear-waste repository at Yucca Mountain.

In denying Heritage’s appeal, the NRC maintained that releasing the redacted portions “could result in harm to the agency,” according to a letter from Darren B. Ash, deputy executive director for corporate management at the NRC. Ash wrote:

It could prematurely disclose the preliminary views of the NRC staff before the NRC staff makes its final decision on whether the U.S. Department of Energy’s license application meets the NRC’s preclosure and postclosure requirements and it could inhibit the open and frank exchange of ideas essential to the deliberative process. In addition, release could create confusion regarding the agency’s final decisions.

Even though the NRC has refused to release the information publicly, the House Committee on Science, Space, and Technology obtained a copy after repeated demands. Earlier this month the committee released a scathing report that documented how the Obama administration undermined U.S. nuclear waste policy by manipulating the process behind the Yucca Mountain decision.

The committee’s report strongly suggested that political pressure from the Obama administration influenced the agency’s decision on Yucca:

SER Volume III demonstrates in excruciating detail the level of technical support among NRC and Department of Energy (DOE) experts in favor of the site’s advancement. Overall, the NRC staff review concluded that DOE‘s Yucca Mountain License Application complies with applicable NRC safety requirements necessary for the site to proceed to licensing for construction.

In addition to the dispute over the Yucca documents, NRC Chairman Gregory Jaczko has also come under fire following a negative report on his actions by the agency’s inspector general. Jaczko previously worked for Senate Majority Leader Harry Reid (D-NV), the chief opponent to the Yucca repository.

Nuclear Regulatory Commission Denies Appeal for Unredacted Yucca Report