Weeks after a freight train containing toxic chemicals derailed in East Palestine, Ohio, and an ensuing controlled explosion took place, residents who were evacuated are now being encouraged to return home. However, they have questioned the health impacts of the chemical spill. 

Operated by Norfolk Southern Railway, the train heading from Madison, Illinois to Conway, Pennsylvania derailed at approximately 8:54 p.m. local time on February 3 due to a malfunction of axle. No injuries or deaths were reported. 

Thirty-eight rail cars derailed and an additional 12 cars were damaged by fire. Twenty cars overall contained toxic chemicals, 11 of which derailed. Five cars contained vinyl chloride, high exposure of which will lead to hospitalization and even death. 

Five toxic chemicals, which are used in plastic manufacturing, have been released to the air. They are vinyl chloride, butyl acrylate, ethylhexyl acrylate, isobutylene, ethylene glycol monobutyl ether, exposure to which can cause shortness of breath, burning in the skin and eyes, coughing, headaches and nausea, to name a few only. 

Up to 2,000 residents in the immediate area were evacuated over a fear of imminent explosion. Some 3,500 fish across 7.5 miles of streams were killed. Five streams meandering about 20 miles south to the Ohio River have the potential to carry runoff from the derailment. 

(Data edited by Yao Nian; graphics designed by Li Jingjie)