June 2007 which "did not name any suspect" and the attorney general made a statement that there would be no criminal charges. According to press reports, the report states that Ameren failed to provide the identity of the person who raised the gauges meant to prevent overtopping and also states that the gauges were moved before investigators were on the scene. KMOX radio in St. Louis reported that the US Environmental Protection Agency assisted by the US Attorney's Office for the Eastern District of Missouri had begun an investigation into violations of the Clean Water Act and has requested the Missouri Highway Patrol's report. The Missouri Public Service Commission (PSC) reopened its investigation and subsequently found the accident to be a failure of Ameren management, stating: ...the Commission can only conclude that the loss of the Taum Sauk plant was due to imprudence on the part of UE (Ameren's AmerenUE Subsidiary). UE was well aware of the catastrophic results likely to occur if the UR (Upper Reservoir) was overtopped by over-pumping. UE knew, or should have known, that storing water against the parapet wall of a rockfill dam was “unprecedented.” UE knew,or should have known, that operating with a freeboard of only one or two feet left no margin for error and required particularly accurate control of the UR water level. Given that circumstance, UE’s decision to continue operating Taum Sauk after the discovery of the failure of the gauge piping anchoring system and the consequent unreliability of the piezometers upon which the UR control system was based is frankly beyond imprudent – it is reckless. UE also knew or should have known that the upper Warrick probes had been reset above the lowest point at the top of the UR." (PSC Report page 71, definitions of Acronyms added) Ameren had 90 days from the date of the report to tell the PSC how it will meet the recommendations of the report, which include a whistleblower rule, changes in safety management structure, financial accounting for the rebuild of the upper reservoir, and single point of management for the rebuild. As of late 2011, Ameren was reported to have paid a total of close to US$200 million in settlements related to the 2005 breach. Reconstruction Federal regulators approved Ameren's plan to rebuild the reservoir, and construction began in late 2007. The rebuilt structure is made entirely of roller-compacted concrete, unlike the