REDDING, Calif. -

Investigators on Friday morning were back at the scene of an explosion that blew a man's hand almost completely off. 

It happened at about 4:30 p.m. Thursday at a home on Chaparral Drive.

Emergency crews responded to reports that a man had suffered blast injuries after working with some sort of rocket fuel that ignited. The exact substance has not been confirmed.

After the victim was taken to the hospital, law enforcement locked down the area and the bomb squad responded.

Late Thursday night, they cleared the scene, but deputies kept watch and evacuations remained in place overnight.

At about 8:00 a.m. Friday, CAL FIRE, Shasta County Fire, the Shasta County Bomb Squad, deputies, and the FBI returned to the location for a further search. 

The bomb squad's robot was deployed to examine materials on the property.

Houses in the area remain evacuated, and the street is closed.

Stay with KRCR News Channel 7 for updates.