One man died and a second was seriously injured Saturday in a fire in downtown Mexico.

The fire was reported around noon at 20 Brown St., a 1½-story house in the Oxford County town.

Firefighters arrived to find heavy smoke and fire, the State Fire Marshal’s Office said.

The man who died was identified Saturday night as Dean Watson, 45. His father, John Watson, 83, escaped the fire unharmed, according to Stephen McCausland, spokesman for the Maine Department of Public Safety.

Mexico Fire Chief Gary Wentzell said Dean Watson’s body was found in the house.

Thomas Brown, who was described by McCausland as in his 50s, was being treated for smoke inhalation at Maine Medical Center in Portland after being taken from the scene by helicopter. Brown reportedly jumped from a porch roof to escape the fire.

Wentzell said he believed all three men lived in the house.

The fire marshal’s office had three investigators on the scene to determine the cause of the fire. They said the fire started on a rear porch and there were no working smoke detectors in the house.

Firefighters from 11 other towns were called in to help fight the fire, “and we still didn’t have enough people,” Wentzell said.

As firefighters came out of the house, Wentzell said, they were checked by paramedics and nine were told they couldn’t return to fighting the fire because of the daytime heat and the heat of the fire.

Wentzell said the damage to the house was so extensive that a local excavating company was called in to knock down the walls.

He said he didn’t think the house was in poor shape before the fire.

“It was quite old, but I’ve seen the house and it wasn’t falling by any means,” he said.