The explosion caused a the terminal to fill with smoke and left several people covered in white dust. Around 30 affected staff were given treatment to counter anthrax, but the whole episode turned out to be a false alarm caused by a power extinguisher.

“The best thing is that it all turn out for the good,” said Dalarna police spokesperson Sven Åke Petters to reporters.

“There were eight people in the premises to begin with, but before the police arrived and the location was sealed off there were several more who had arrived, including emergency personnel,” said deputy county medical officer Astrid Danielsson.

Police received an alarm over the explosion at 8.20am on Wednesday morning. The premises filled with smoke and the white powder filled the air, Petters told The Local earlier on Wednesday.

Dalarna police led the investigation into the explosion although the Security Service followed developments after having been informed of the incident.

Borlänge post terminal is operated by Posten, formerly Sweden’s postal monopoly, and serves the county of Dalarna. The terminal was evacuated after the incident to allow for police forensics to conduct an examination.