South Wales Police received numerous reports of an explosion at a property in Church Road, Seven Sisters today at 2.05pm.
A number of properties and vehicles in the street have been damaged and the area has been evacuated. Three people, one adult and two children, have been injured in the incident.
The two injured children have been transported by air ambulance to Southmead Hospital, Bristol and the adult was taken by ambulance to Morriston Hospital, Swansea. Their injuries are described as serious.
The road will remain closed overnight and diversions are being put in place.
Around 14 properties have been evacuated and Neath Port Talbot Council have opened a rest centre with full support for these residents.
The cause of the explosion is under investigation.