A new report from the NTSB says that PG&E detected natural gas at the Hayward explosion site after crews supposedly capped the leak. Here are what other details it revealed about the hours leading up to the explosion that sent three people to the hospital.

HAYWARD, Calif. -- At least six people were taken to the hospital Thursday morning after a massive explosion caused a large fire in Hayward, California, fire officials say. The Alameda County Fire Department says crews responded to the three-alarm fire.

Authorities in southern Colorado are investigating after a sudden explosion damaged a building and startled nearby residents.

A Eustis business exploded on Dec. 4, sending one woman to the hospital with critical injuries. Officials say the explosion occurred shortly after the city shut off a gas leak. A woman and her service dog were inside the building when it exploded.

A new report from the NTSB says that PG&E detected natural gas at the Hayward explosion site after crews had supposedly capped the leak.