Two Germans were in the truck when it crashed on the E18 motorway near Köping, 150 kilometres west of the capital. The driver was rescued from the vehicle and taken to hospital.
“I don’t yet know how seriously injured he is yet,” said Ulf Palm, spokesman for Västmanland police.
Palm said the German-registered truck’s cargo contained riogel, a highly explosive substance used in the construction industry for tasks such as rockblasting.
An area with a radius of 400 metres has been cordoned off around the truck, but police said there was no danger to the public. Diversions were being put into place around the scene, with the incident expected to cause delays for drivers. Traffic will be directed through Köping until the area has been made safe, police say.