It's vinyl chloride, not PVC, vinyl chloride is used to make PVC. Vinyl chloride has a boiling point of 7.9 degrees Fahrenheit or -13.4 Celsius.
Because of its low boiling point it is subject to flash evaporation. How do you make a train derailment with train cars containing a toxic and flammable substance that will flash evaporate when exposed to air and said cloud of flash evaporated can ignite for a secondary explosion safe for workers to clear? You blow it up so that all the vinyl chlorate immediate evaporates allowing you to also contain and control any secondary explosion.
What is vinyl chloride, the chemical released from the East Palestine train cars? After a controlled burn of the chemical, people saw plumes of smoke from miles away. Pittsburgh Post-GazetteIt makes sense they're fucking with journalists because Norfolk Southern lobbied to block new safety regulations that could have prevented this. Ohio is a critical crossing point for rail and semi cargo transport. Cops protect and serve the interests of capital.
Rail Companies Blocked Safety Rules Before Ohio Derailment Norfolk Southern helped convince government officials to repeal brake rules — and corporate lobbyists watered down hazmat safety regs. The Lever