Fire at Janakkala fireworks warehouse caused by damaged pyrotechnics, investigation finds

A fire at a professional fireworks storage facility in Janakkala, Finland, last November was likely caused by damaged pyrotechnics, according to an investigation by the Finnish Safety and Chemicals Agency (Tukes). Two employees were injured in the blaze, which sent explosions visible over a wide area.

The fire broke out at a warehouse owned by Pyrokratia Oy, a company specialising in fireworks displays, Tukes confirmed in its accident investigation report released Tuesday. The incident occurred when an employee inspected a cardboard box containing unused professional fireworks returned from an event in France. Upon handling one of the items, it ignited, rapidly spreading to other fireworks in the same container.

The flames then spread explosively to multiple containers across the storage area. Investigators determined that the returned fireworks had likely been damaged during transport or handling, making them more susceptible to ignition from static electricity or mechanical friction. The report also noted deficiencies in how the products were repackaged—fireworks were placed in the same box without protective filling material, allowing them to shift during transit.

An estimated 3,300–3,550 kilograms of fireworks burned in the fire, which spread further due to exploding pyrotechnics and nearby parked vehicles. At the time of the incident, five containers had their doors open for inventory purposes, accelerating the blaze’s expansion.

Tukes has issued several recommendations to improve safety across the industry, including clearly defining responsibilities for packing and returning fireworks after displays. The agency also advises conducting risk assessments before transporting or storing returned products and ensuring containers are clearly labelled with their contents. Storage areas should be designed to minimise the number of open containers at any time and prevent vehicles from parking near them.

The fire prompted the evacuation of nearby residents within a one-kilometre radius, though they were allowed to return the following day. The warehouse area remained cordoned off for several days as a precaution. The two injured employees did not sustain permanent injuries, according to Tukes.