The owner of Watson Grinding tells us it was a propylene gas explosion, which sent two people to the hospital with non-life-threatening injuries.
WATCH: Mega Doppler Radar captures explosion over northwest Houston Friday morning
The explosion could be felt for miles, with viewers from Atascocita and Kingwood to the west side of town, calling ABC13 to report they could hear it.
WATCH: Some cameras caught the huge blast, others recorded the enourmous sound of the explosion.
The Harris County Sheriff's Office says that no evacuations are in place.
WATCH LIVE: Massive explosion in NW Houston felt across region
Witness describes NW Houston blast