A train accident occurred in Ohio in the United States. 50 cars of the train were derailed o damaged, and 11 of the 20 cars carrying hazardous chemicals were derailed. Vinyl chloride is a monomer for synthetic polyvinyl chloride, which is mainly used in the manufacture of polyvinyl chloride plastics, that is, PVC plastics. After the incident, Norfolk Southern Company, the train operator, carried out the so-called "controlled release" operation of vinyl chloride carried in five of the carriages and discharged it into a pre-prepared tunnel to ignite it.
The black smoke is thick in the videos...