GAS company bosses have assured the public that there is no imminent danger following a major leak in the centre of Darlington.
Staff from Northern Gas Networks (NGN) are working on the inner ring road, which is currently undergoing remodelling work.
Members of the public have reported a strong smell of gas in the area.
Eyewitnesses described hearing the sound of gas leaking at a considerable pressure.
Northern Gas Networks told The Northern Echo there was no immediate danger.
It is understood the leak happened when contractors working on the ring road hit a gas main.
A 'No Smoking' sign has been put up close to the source of the leak.
An NGN engineer said colleagues were working to reduce the pressure by altering valves elsewhere in Darlington.
Once this has been done, the engineers at the scene will be able to get to work repairing the leak.
Traffic has been reduced to one lane while the leak, which was reported at about 2.30pm today, is fixed.
Steve Pigott, emergency officer for NGN, said: “Emergency response engineers from Northern Gas Networks are carrying out essential work to repair a medium pressure gas main in St Cuthbert’s Way, Darlington.
“There is currently a strong smell of gas in the area, but we would like to reassure the public that the situation has been made safe.
“Apologies for any inconvenience caused while this repair work is carried out.
“The gas supply to customers in the area has not been affected.
“If you smell gas you should call the National Gas Emergency Service on 0800 111 999 immediately, your call will be answered at any time of day or night and an engineer will be sent out to assess the situation promptly.”