A train whose 15 tanker cars carrying yellow phosphorus overturned in Western Ukraine Monday, catching fire and releasing pollution, is now on its way back to Kazakhstan, the Ukrainian emergencies ministry said Thursday, according to RIA Novosti.

The accident occurred when the freight train traveling from the Central Asian country to Poland derailed outside Lvov, near the Polish border. Several cars caught fire, sending poisonous fumes over a large area.

Official reports said 49 people, including 15 children, were harmed by the fumes and 14 populated areas with a total of 11,000 residents were affected. During the cleanup operation, 18 emergency workers were also poisoned. Some 800 people were evacuated from the area.

The train will go to Kazakhstan via Russia. A spokesman for Russia`s rail monopoly Russian Railways earlier said all required safety measures would be taken to escort the train along the route, bypassing populated areas in Russia.

The Ukrainian government said the accident was the country`s worst man-made disaster since the 1986 Chernobyl tragedy. A special commission has been set up to investigate the accident, and criminal proceedings have been launched.

The Ukrainian government has allocated $2.8 million to eliminate the consequences of the disaster, the country`s finance ministry said.