AUBURN TOWNSHIP -- Federal investigators are stepping in to look at a fatal fuel tank accident this weekend that left a teenager dead and seriously injured his brother.

Timothy Haas, 17, died after being overcome by fumes while he and his brother were trying to save their father, who was cleaning a fuel tank in Geauga County.

The Occupational Safety and Health Administration is investigating the tragedy, which happened Friday evening in Auburn Township.

Timothy Haas' 19-year-old brother, Paul, remains in critical condition at MetroHealth Medical Center.

Their father, 49-year-old Bruce, was contracted by Ullman Oil to clean the fuel tank.

"They were changing product and over time, residue develops in the tank and when you put another product in, you have to make sure that it's clean so that they don't have a large reaction," said Auburn Township Fire Chief John Phillips.

Investigators said Bruce Haas became disoriented and could not find the exit. His sons, who were not there to work, realized their father was in trouble and crawled into the tank that measures 30 feet wide and 75 feet long.

An Auburn Township firefighter pulled Bruce to safety but crews became worried about exposure and possible explosions.

It took another four hours for a specialized confined space rescue team to get the brother out, but it was too late for Tim.

"We are taught not to risk a life to save another, for very good reason. If our fireman would have become trapped, they would have become hurt, it would have compromised our rescue effort. One more person to try to get out of that tank," said Phillips.

Bruce Haas was treated and released for his injuries.

OSHA officials said it could be a couple of weeks before it is decided if any citations or fines will be issued.