A reporter for Chard and Ilminster News has tweeted this photo purporting to show the closed service station at Southfield roundabout.
A large heavy goods vehicle can be seen in the background surrounded by police and ambulances.
The scene at Southfields Roundabout services. Police cordoned off a HGV. Appears to be around 20 people inside it. http://t.co/aUTBj5wVHG