HOUSTON, Texas - Police are blocking off streets in Houston, Texas after a reported explosion at a building northwest of downtown Houston. 

Police said they started getting 911 calls about the explosion around 4:30 Friday AROUND 4:30 and confirm they are blocking off streets around this building.

According to our CBS affiliate in Houston, the building impacted is some sort of an industrial facility.

Officers said there could be a secondary explosion and the air quality may pose a threat, so they are asking people to stay away from the area.

Right now, it is not clear what caused the explosion or if there are any injuries.

This is a developing story...