Seven people were injured after an explosion at a workplace in Trangsund, south of Stockholm.

It is an accident in connection with a sheet-metal polishing at the workplace, reported Swedish Television (SVT) on Tuesday.

The explosion occurred while a suction machine was being serviced, Anders Bryngelsson with the Stockholm Police told SVT.

"For some reason the shavings vacuum exploded, causing a huge amount of smoke to spread," he said.

One person working with the vacuum sustained serious burns and has been taken to the hospital. Two people damaged by the smoke were also transported to the hospital, while four other people have breathed in the smoke but do not need transport to the hospital, SVT reported.