Police say the driver is inside the building and may be armed.
All of the employees have been evacuated.
A Baltimore County police spokesperson says the vehicle rammed the WMAR-TV studios in Baltimore around noon ET. People in the area are being told to steer clear.
Another TV station put a helicopter in the air and viewers can see the giant hole in the building.
WMAR tweeted about the incident saying it was a dump truck that rammed the building.
The station says all employees are safe and accounted for, but the man who was driving the truck is apparently still inside.