It seems very strange that they'd rather burn the vinyl chloride instead of attempting to capture or recover it, both from an environmental and economic perspective.
Vinyl chloride, when burned, can create poisonous byproducts such as phosgene and carbon monoxide. Vinyl chloride that leaks into the environment is a carcinogen that can cause damage decades into the future. It's a tradeoff, but probably a good one. We can deal with the acute danger of poisonous gas by temporary evacuations and air filters. Once a carcinogen is in the ground or the water, though, it's much more difficult to get it all cleaned up.
