Fire crews are tackling a blaze at a garage on an industrial estate in Darlington after reports of an explosion.
A loud band was heard at about one o'clock this afternoon on the Cleveland Industrial Estate on the Forge Way.
Durham and Darlington Fire and Rescue's spokeswoman said: "We currently have four fire appliances and one aerial ladder platform in attendance.
"This was a single storey premises, around 15m by 10m used for gas conversion for motor cars, well alight."
A Durham Police spokeswoman said: "It is believed that one person was hurt.
"Fire, ambulance, air ambulance and police are in attendance.
"The has been area cordoned off and could be for some time due to the presence of cylinders."
The air ambulance is taking one casualty to Newcastle's Royal Victoria Infirmary.
He's believed to have arm and head injuries.