The A350 has been closed in both directions following a lorry fire.
Several fire crews, a water carrier and other fire appliances were deployed to the incident just off the junction 17 roundabout towards Chippenham at around 8.30pm.
A spokesperson for Dorset and Wiltshire Fire and Rescue Service said: “Crews have attended a lorry fire with a hazardous load this evening, the lorry was carrying a large quantity of used car batteries.
”Crews extinguished the fire using four breathing apparatus and two main jets.”
In total, five engines, one water carrier, a command support unit and an operational support unit equipped with enhanced environmental protection equipment attended the incident, were all in attendance.
The road is expected to reopen by 11pm.
A spokesperson for Wiltshire Police said: “We are currently assisting with a lorry fire on the A350 north of Chippenham, close to the M4 junction.
“The northbound carriageway will reopen shortly, but the southbound carriageway is likely to remain closed for the next hour-and-a-half.
“Please find alternative routes.”