The Pori Brigade, a unit of the Finnish Army, will begin using genuine chemical warfare agents including mustard gas and sarin in defence training.
Finland has previously used substitute chemicals rather than genuine warfare agents in its chemical warfare defence training.
According to tabloid Iltalehti, the army said the primary purpose of the new chemical warfare training is to equip military personnel with the skills and abilities required for combat in an authentic environment. IL reported that the army said other countries, including Sweden, have been using chemical weapons in their training for years.
The Pori Brigade has plans to set up a separate area exclusively for chemical warfare drills. The exercises will be the first of its kind in Finland, and the brigade will be the only entity in the country to provide instruction concerning chemical weapons.
Around three hectares of land will be used as a training area this autumn, and exercises for military personnel will begin in January Instructions on chemical warfare will also be provided to other authorities, according to the army.
The chemicals in the weaponised agents are known to be lethal to humans and hazardous to the environment, but the army has said that the training will pose no threat to the surroundings or to bystanders in the area.
Deadly chemicals: Sarin and mustard gas
The chemical warfare agent mustard gas, also known as sulfur mustard, can form large blisters on exposed skin and in the lungs and is also a known carcinogenic. Mustard gas was first used during the First World War by the German army. Most recently the gas was used by the terrorist organisation Isis in 2016, according to Syrian state media.
Sarin, considered a weapon of mass destruction by international convention, is a synthetic compound nerve agent that can be lethal even in very low concentrations. Unless victims receive an antidote quickly, they generally suffocate from lung muscle paralysis when exposed to the substance.
Chemical warfare was outlawed by the Geneva Protocol of 1925 and was again prohibited by the Chemical Weapons Convention of 1993.
EDIT 18.9.2019: An earlier version of this story erroneously claimed that the first use of mustard gas was by the British Army against Soviet Russia occurred in 1919. The first use was actually by German troops in Poland in 1915.