A routine cleaning in a California water tank Wednesday morning ended with a worker fatality, after a makeshift floor collapsed, killing one man and injuring another.

Authorities said the two were contracted employees sent to clean welding debris left in the 15’ by 10’ tank at an Oildale power plant from a welding repair done the previous night.

Killed in the incident was 54-yer-old Barry Snelson of Bakersfield, who died of a head injury. The other worker suffered a broken leg.

"A repair last night was done through welding, and this morning the two gentlemen were there to clean up the remnants of the welding, and something happened with the floor," said Eric Coughran, Kern County Fire Department. It took firefighters three hours to reach the two men through the top of the water tank.

Cal-OSHA said the floor was temporarily made for workers to stand on during repairs.

Officials said there were no toxic fumes in the water tank. "The tank was a watering filter system," said Coughran.

Cal-OSHA spokesman Dean Fryer said his agency will investigate what he called an unusual case. "I haven't heard of this type of incident before so it may not be a very frequent type of occurrence," said Fryer.

The two men were contracted employees for a Bakersfield company, Brahma Group, Inc.