A person who was at the industrial premises alerted about the fire at 17.58 on Thursday afternoon.
"Right now we are creating a snapshot of the fire," says Viktor Danielsson, who is a staff commander at Rädsam Mälardalen.
Several of the rescue service's forces from Västerås are in place.
- We also have reinforcements from Skultuna and Enköping, says Danielsson.
In order to facilitate the work of the emergency services, the police are on site and are blocking the area around the building.
"At the moment we are only helping and do not know how this has gone," says Daniel Wikdah, the police spokesman.