A report in the St. Louis Post-Dispatch claims AmerenUE had a warning that part of the wall around its Taum Sauk Reservoir could collapse. The newspaper reports a plant superintendent sent an e-mail to several supervisors warning of the danger. The e-mail was sent less than three months before the failure. The Post-Dispatch reports the superintendent at Taum Sauk, Richard Cooper, said in his memo that water had overflowed the northwest wall of the reservoir and had washed away rock at the base of the reservoir wall. The newspaper adds AmerenUE never reported that overflow to federal regulators.