Y2013-02 Heating of a container with residual explosive waiste at the Vihtavuori explosive factory in Laukaa on 10 July 2013
In Vihtavuori, Laukaa, a hazardous situation occurred on Wednesday 10 June 2013, when the temperature began to rise of a container holding residual explosive waste stored in the yard of a storage facility. The container was one of more than 200 similar containers stored in the yard, all of which contained explosive waste. The adjacent storage held 40 tonnes of explosives. The situation was deemed so grave that the Rescue Services decided to evacuate the central Vihtavuori area and restrict road, rail and air traffic in the vicinity of the factory area. Approximately 21 hours after the rise in temperature of the container had been noticed, a rescue crew managed to cool the container down and move it to a safe location. No fire or explosion occurred.
The residual explosive waste had originated from a mine. In the mine, positioning of charges in boreholes from below had failed, resulting in the liquid emulsion explosive spilling onto the floor of a tunnel. While cleaning the spilled explosive, the miners accidentally collected detonators lying on the floor, as well as rock formed of fine powder mixed with water. The residual explosive waste thus created was transported to Vihtavuori, to be disposed of there by the manufacturer. At the time, the factory already housed hundreds of containers of residual explosive waste, all returned by customers. This caused the time for the disposal of this particular container to be brought forward. The heating of the container was detected one year from the incident in the mine. The heating process was caused by a chemical reaction in the mix of explosives and rock powder. In breach of the licensing terms, neither the operating procedures of the factory itself nor the authorities responsible for monitoring intervened in the storage of containers holding explosive waste.
On the basis of previous experience, the heated container was treated with due caution during the rescue operation. At the beginning, representatives of the explosives factory were unable to provide the Rescue Services with the information they needed on the nature of the chemical reaction and the potential risks posed by the heating process, all of which delayed the rescue operation. The evacuation of the large area was hampered by a lack of plans and instructions. Finland has no previous experience of evacuation operations on this scale.
The Safety Investigation Authority recommends that the Finnish Safety and Chemicals Agency develop a monitoring process and maintain online monitoring registers to enable real-time inter-action and monitoring. The Finnish Safety and Chemicals Agency should require that the facilities it monitors produce functional and documented procedures for the detection, assessment and correction of nonconformities, and that all defects detected by the authorities be handled in line with such procedures. These monitoring procedures should also include clear criteria by which authorities must take coercive measures rather than resort to the provision of advice, the conducting of negotiations or the issuance of orders. The Ministry of the Interior should ensure that guidelines be prepared for the implementation of large-scale evacuations.