Results: An accident or an act of terrorism?

On Tuesday, June 19th at the Gaylord Opryland Hotel in Nashville there was an explosion that caused $750,000 worth of damage. No one was injured although some 5,000 guests were evacuated for as long as seven hours. There was a law enforcement convention going on at the time. Investigators say the blast was caused by natural gas and high-pressure steam combining in a line, causing a heat exchanger to explode. What do you think?