A last-minute announcement came in Wednesday regarding a press briefing to announce a new analysis of the root cause of the Dec. 22 TVA coal ash spill in Harriman, Tenn. Fortunately, I was able to watch the briefing occur online despite being excluded from the event upon request. But despite this misstep by TVA, I was glad to see that this important 1,400-page report, which seems to be created by a reputable group, has provided quality analysis that clearly identifies some of my and other colleague’s preexisting thoughts about the causes of the spill, and also presented some new ideas.

I’ll summarize some outstanding conclusions from the analysis to begin. First, this event was not a natural disaster, as previously proposed by some. Secondly, the report information shows exactly why wet stacking is so problematic and should not be used in future site development. And third, there was a breakdown in the use of appropriate engineering techniques due to the overlook of slime material in the site development area.

To expand, it appears that the proper characterization was not done during the expansion of this site. The report points to structurally weak ‘slimes’ in the foundation from historic ash disposal as a significant contributing factor. One would think that TVA, with its vast engineering experience, would have known to look for this material. Below is a graph provided in the analysis that shows the main weakening contributors to the site.

The report also leads one to the conclusion that wet storage of ash causes significant engineering risk. My hope is that this will push Congress and EPA to act quickly to regulate coal ash and phase out wet storage. When we consider some of the positive repercussions of this unfortunate disaster, this righting by way of regulation would be on the top of that list.

The fact that the report lays to rest the misinformation pointing to the event as a natural disaster shows that TVA could and should have made better decisions during the development process of this ash site, which is worrying for many reasons, one being the fact that this is only one of many ash sites TVA has developed in the same fashion. There is no evidence that this is anything other than a failure of human engineering to contain a toxic material, and other sites throughout the U.S. should be appropriately altered to prevent further disasters.

Within this analysis, we are looking at issues that could have been avoided, meaning that TVA should be held accountable for mistakes that led to this untimely event. I certainly hope that alterations in management of coal ash sites will be made due to this analysis and further research will be conducted moving forward.

Read coverage of this new analysis release in the Tennessean, Associated Press and the Knoxville News Sentinel.

Please also visit our coverage page kept updated following the Dec. 22 spill. It includes releases, statements, my Senate testimony and additional information.