Tennessee Valley Authority President and CEO Tom Kilgore, left, and TVA spokesman Mike Bradley, are shown leaving the federal courthouse in Knoxville.KNOXVILLE, Tenn. (AP) — The Tennessee Valley Authority's inspector general testified Thursday that he stands by his report that criticized the utility for its December 2008 coal ash spill, saying TVA for years failed to heed advance warnings and afterward refused to include management issues as a possible cause.

As chief executive of the utility's independent watchdog agency, General Richard Moore testified at a trial on lawsuits that seek damages caused by more than 1 billion gallons of toxin-laden sludge that spilled on a rural riverside community.

TVA contends environmental tests and medical surveys show the spill caused no harm and that as a federal agency it has immunity for all but proven compensatory damages. A $1.2 billion cleanup is continuing.

The inspector general's report in 2009 said TVA ignored an engineer's internal memo in 1985 and consultant warnings in the years before the spill about the coal ash storage facility at the coal-fired Kingston Plant on the Emory River west of Knoxville. Moore said TVA at a news conference after the spill wrongly failed to include management issues as a possible cause.

Moore said a consultant hired by TVA after the spill to find the cause was not allowed to look at management issues.

In questioning in the fifth day of the bench trial, TVA attorney Edwin Small confronted Moore with emails that he had sent during the spill investigation and while he and top TVA executives were scheduled to testify to congressional panels afterward. Small described the inspector general's report as the "centerpiece" of the court fight.

Asked by plaintiff attorney Jeff Friedman if he stands by his criticism of TVA's training and maintenance before the spill, Moore testified, "There's nothing in the report I want to change."

"There were poor engineering practices that outside consultants that we talked to were surprised to see," Moore said.

Small also asked Moore about his emails sent as inspector general to co-workers, including one in April 2009 that referred to hiring a consultant to assist in the investigation and saying the reason was "to step out with some credibility and say TVA is wrong." In November 2009 he sent an email asking staffers for suggestions on "what we can say about what they have done to stop their lying ways. In other words, what have they done to avoid lying about stuff like the root cause analysis?"

Moore in another email sent to his staff also said "Let's focus on a lean power punch here." In another he asked an investigator in his office to quickly interview some top TVA executives to see if they were coached about what to say in explaining the spill.

"That wasn't said in the most artful way," Moore testified.

Coal ash contains arsenic, selenium, lead and mercury, and those contaminants can pose health risks.

The EPA has proposed either regulating coal ash as a special hazardous waste, bringing it under direct federal enforcement as favored by environmentalists, or siding with the coal and ash-marketing industries in designating it as non-hazardous and leaving regulation to the states.

Some industries use "coal combustion residues" in wallboard and some concrete products and contend there is no evidence that it is a health hazard. Coal ash recyclers and manufacturers contend tougher federal regulations would place a stigma on the substance and hinder efforts to reuse the ash.

Testimony resumes Monday.

TVA supplies power to about 9 million people in Tennessee, Kentucky, Alabama, Mississippi, Georgia, North Carolina and Virginia.