KEY WEST, Fla. -- It won't happen again -- that's the word from officials in Key West after carbon monoxide killed a man at a popular hotel.

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The Key West Fire Department and police departments have not yet concluded their independent investigations, but Friday the secretary for the Department of Business and Professional Regulation flew from Tallahassee to accept some responsibility for what went wrong at the Doubletree Grand Key Resort, Key West's second-largest hotel.

"I am so sorry for their loss," Holly Benson, secretary for the DBPR, said.

At the job less than one month already, Benson admitted one of her own hotel specialists failed to a secure that a boiler had been inspected by the property authorities and that the certificate was posted as required because it exceeded 400,000 British thermal units.

"Not all boilers require assert; it's only above a certain BTU level that the certificate is required," Benson said.

It's unclear if the certificate was on the boiler or not because the boiler was at 500,000 BTUs.

According to the state agency, that would have been the responsibility of the fire marshal.

"It would have been properly inspected if the inspector identified that boiler certificate," Ron Russo of the DBPR said. "The inspector did not identify that boiler certificate. It was noticed that it was not there."

Thomas Luder died from carbon monoxide poisoning on Dec. 27 inside room 416 at the hotel.

Alleged improper emissions from a nearby boiler were the cause, officials said.

Earlier this week, Benson dispatched a group of seven inspectors to Key West hotels that have boilers above 400,000 BTUs.

She said it was all in an effort to reassure potential visitors to Key West that this type of thing will never happen again.

"We want to make sure that all the visitors who come to Key West and come to Florida feel safe in using these establishments," Benson said.

The Doubletree will reopen on March 1, hotel management told NBC 6's Carlos Vergara.

The state fire marshal's office, the City of Key West Fire Department and Police Department will each forward their investigation onto the state attorney's office, who will then decide whether any criminal charges will be filed.