FIRESTONE, Colo. — Firefighters battled a large house fire after an explosion on Monday afternoon sent at least two people to a hospital, the Frederick Firestone Fire Protection District said.

It happened around 4:45 p.m. in the 6300 block of Twilight Avenue near Colorado and Firestone boulevards.

The explosion was so intense, it leveled the two-story home. It took awhile for firefighters to put out the flames, and on Monday night, the scene was still too hot and unstable to go in to see if there were more victims.

A man and a woman were inside the home when it happened, firefighters said. They were taken to a hospital in unknown conditions, with the woman being airlifted by Flight for Life.

Neighbors said the man works for Firestone Public Works and that he came home to fix a broken water heater. It’s not known if that’s connected to the explosion.

There were children around the home when the explosion happened, but all were reported safe, officials said.

The explosion rocked the neighborhood, with residents as far as three blocks away reporting they felt the ground shake.

At one point, the smoke coming from the house was so bad that neighbors in the area were evacuated.

“We live about three blocks away and felt the explosion or whatever it was so I went out to see it,” Abe Vega said. “It sounded like somebody had hit our house or something. I went out see all the smoke and fire.

“By the time I got over here, the house was literally collapsed,” Jack Brown said. “But luckily the kids got out.”

The investigation into the cause of the explosion could take weeks.

The American Red Cross said it is assisting two adults from the house and two adults from a neighboring home who were affected.