Some kind of cleaning work has been going on in a fuel tank at the petrol station, says the police's press spokesperson Magnus Jansson Klarin.
One person is seriously injured and has been taken to hospital by ambulance helicopter, the police write on their website.
The police were alerted at 13:59 on Monday.
The police cordoned off a larger area around the petrol station due to the risk of further explosions, but later in the afternoon the outer cordons were lifted.
"The area around the actual petrol station will continue to be cordoned off pending a technical investigation", the police write on their website.
It is still unclear why the explosion occurred.
The police are investigating the incident as gross negligence leading to bodily harm through a workplace accident.
