Nine employees in the Oulu Oritkari industrial area were exposed to formic acid on Tuesday when a plastic container full of the acid was damaged.
According to the rescue department, acid started spilling from the container around 10am when a truck dented it, resulting in the spill in both inside and outside the premises.
The workers exposed to the acid were taken to hospital for examination.
Formic acid is a colourless, pungent and corrosive liquid, largely used as preservative and antibacterial agent in livestock feed.
