After a massive spill of coal ash at one of its power plants last December, the Tennessee Valley Authority hired an outside consulting firm to find out what went wrong. But according to a recent report by TVA’s inspector general, the firm’s analysis was too limited. And that was because the authority’s law department narrowed the study’s scope in an attempt to limit TVA’s legal liability.

TVA’s office of general counsel “predetermined the choice that would be made between accountability and litigation strategy,” inspector general Richard Moore wrote in his 111-page report. Neither TVA nor the GC’s office responded to requests for comment about his findings.