SAND SPRINGS, Oklahoma - Sand Springs fire investigators are trying to determine what caused a house fire near 2nd Street and McKinley Avenue.

Firefighters say the outside of a home on Roosevelt Avenue appears to be sturdy and there's not much damage but inside the home is a totally different story. A neighbor called 911 after seeing smoke billowing from the home.

Firefighters say the basement was on fire and those flames got into the walls. They say the thick sheetrock trapped a lot of the flames, making it difficult to put the fire out.

Deputy Fire Chief Justin Hall says crews were inside when part of the floor fell through, but no one was hurt. Hall talked about some of the challenges they faced in getting the fire under control.

"There's already an inherent danger. They're trying to find their way around the house and this fire was not showing itself very well in there so they're having to crawl around in that smoky atmosphere and try to find that fire," said Hall.

Fire crews say no one was inside the house when the fire started. Firefighters say they had to rotate in and out to get oxygen because there was so much smoke.

The district fire chief said the electricity and gas were both on inside the house but those have since been shut off.