Motorists are facing delays on the A465 following a collision between Neath and Llandarcy on Friday.
Traffic Wales has confirmed that lane two of the southbound carriageway is currently closed while emergency services deal with the incident.
Drivers travelling through the area are being advised to allow extra time for their journeys, with congestion expected as traffic passes the scene.
Details regarding the number of vehicles involved or whether anyone has been injured have not yet been released.
Traffic Wales said emergency services remain in attendance and the lane closure is likely to remain in place while the incident is dealt with.
Road users are urged to approach the area with caution and follow any instructions from emergency services and traffic management teams.
This is a developing story and will be updated as more information becomes available.
