As municipal, state and federal authorities investigate the cause of Sunday's deadly explosion at the Kleen Energy Systems plant in Middletown, we need to know more than simply what happened.

One question to consider: Could the disaster that killed five workers and cast in doubt the future of a nearly completed, $985 million power plant have been averted if workers heeded urgent federal guidelines issued only a week earlier?

On Feb. 4, the U.S. Chemical Safety Board, a federal agency that investigates serious chemical accidents, approved new safety procedures for purging gas pipes after an investigation into a gas explosion that killed four people last year at a Slim Jim factory in North Carolina.

Though it may be too soon to say if there were any similarities between the two accidents, Sunday's explosion in Middletown occurred during just such a purging.

U.S. Rep. Joe Courtney, a Democrat whose 2nd District includes Middletown, surveyed the site Monday and said that, in light of recommendations resulting from the North Carolina accident, he's concerned that the Occupational Safety and Health Administration takes too long to approve and enforce new regulations.

"OSHA seems to be where rules go to die," Brian Farber, Rep. Courtney's communications director, said Tuesday.

Rep. Courtney received a commitment for a congressional hearing on the accident, and we welcome such an inquiry. It is expected to focus on OSHA policies protecting the safety of plant workers and nearby residents.

At the same time, Gov. M. Jodi Rell has ordered two separate probes - one into the cause of the accident and the other to recommend any needed changes to the state's safety codes.

Meanwhile, law enforcement authorities, who are treating the blast site like a crime scene, say it does not appear the explosion was set off intentionally but nevertheless are looking into the possibility of criminal negligence.

All these investigations must be expeditious but thorough, and focus on safety, not politics. We cannot afford to waste time, and potentially more lives, by dithering or grandstanding.

Finally, consumers need to know what impact, if any, the accident will have on their electric bills. Though officials have said there won't be any immediate effect because the 620-megawatt gas-and-oil fired plant, designed to power up to 310,000 homes, had not yet gone online, the surplus power it generated eventually would hold down rates.

As for the heavily damaged building, it remains unclear if Kleen Energy Systems LLC and its largest investor, Energy Investors Funds of Boston and San Francisco, will rebuild the plant.