© REUTERS / Aziz Taher
A view shows damages at the site of Tuesday’s blast in Beirut’s port area, Lebanon on August 5, 2020.
In Finland, the substance is used as a fertilizer and as part of the manufacture of explosives, and strict regulations have been set for its storage.
In Finland, the storage of almost three thousand tonnes of ammonium nitrate in a central location would be illegal, says Aki Ijäs, Senior Inspector of the Finnish Safety and Chemicals Agency Tukes.
According to the Lebanese authorities, yesterday’s explosion in Beirut was caused by ammonium nitrate, which stored up to 2,750 tonnes in the port.
– I do not know the legislation of other countries so precisely, but such storage would be unequivocally prohibited in Finland, Ijäs says.
According to Wednesday’s estimates, the explosion was caused by a fire in the port, which ignited a huge amount of ammonium nitrate in another warehouse.
According to unconfirmed information, ammonium nitrate was once seized from a ship that entered the port. In Finland, ammonium nitrate is used both as a fertilizer and in the manufacture of explosives.
According to Ijäs, the substance has strict storage regulations.
– It has been given its own safety distances for storage, ie how far the warehouses must be from apartments, buildings, assembly areas and roads.
– Efforts have also been made to prevent the possibility of a major accident by the fact that if it is a really large warehouse, the substance must be stored in separate stacks.
– The substance should be stored in stacks of a maximum of 100 tonnes (industrial bags) to prevent accidents of this kind that affect kilometers from the site, Ijäs says.
There are few large stocks in Finland
According to Ijäs, there are few stocks of more than 100 tonnes in Finland. In addition, other storage regulations are intended to prevent accidents.
– Fire prevention is central to storage and no organic combustible material can mix with ammonium nitrate. It is an oxidizing substance that accelerates the combustion of organic matter. In addition, provision shall be made for the stores to be kept locked so that outsiders cannot gain access to the substance.
According to Ijäs, the explosiveness of a substance depends, among other things, on its nitrogen content and purity.
– Yes, there are differences, and in Finland, too, different grades of ammonium nitrate are distinguished at the regulatory level. For example, to fertilizer grades that also contain such components as ammonium nitrate, where the nitrogen content is not high. They are not so explosive. On the other hand, all contaminants and organic combustible material may increase explosiveness, Ijäs says.
According to Ijäs, the condition or storage conditions of the ammonium nitrate which may have been involved in the Beirut explosion are not yet sufficiently known to enable its concentrations or purity to be assessed.
According to the Tukes guidelines for fertilizers, the substance forms toxic flue gas when heated. In addition, if the temperature in the stock containing the substance continuously rises above thirty degrees, the granules of ammonium nitrate become more porous. This also contributes to the explosive sensitivity of the substance.