In the Balvano train disaster of 2/3 March 1944, some 426 people illegally riding a steam-hauled freight train died of carbon monoxide poisoning when the train stalled on a steep gradient in the Armi tunnel. The accident occurred in southern Italy, near Balvano (Basilicata).
Naples suffered severe wartime shortages, encouraging an extensive black market. By 1944, the Allies had already defeated the fascist government of Benito Mussolini. Opportunists in the city began bartering fresh produce for commodities brought by servicemen, and stowed away on freight trains to reach their suppliers' farms. The railway companies also experienced shortages of good quality coal. The burning of low grade substitutes produced a large volume of odorless, poisonous carbon monoxide gas, a critical factor of the ensuing disaster.
Just after 6 p.m. on 2 March 1944 the freight train 8017, reached Eboli, beyond Battipaglia. At about 11:40 p.m. the train carried many illegal passengers. The tunnel was graded steeply and the freight train grossly overloaded with its passengers. The train stalled with almost all the cars inside the tunnel. The passengers and crew were overcome by the smoke and fumes so slowly that they failed to notice the dangers. Most of the few survivors were in the last few cars which were still in the open air. Much carbon monoxide gas was produced as a by-product of combustion, and carbon monoxide poisoning is a well recognized danger when machines are used, or fires occur in enclosed environments. It combines with haemoglobin when inhaled, so the victim dies of anoxia (lack of oxygen). It is still the principal cause of death in mine disasters after a fire or explosion.