Hydrochloric acid, an indispensable part of our digesting system, will only be deadly at high concentrations. Greenpeace uses this fatal accident to say that this can happen with chlorine or hydrochloric acid too. In fact nothing is impossible, but because chlorine is sixty times less toxic, with the same circumstances, you will have sixty times less victims. And with hydrochloric acid, that would give six hundred times less victims. So you can see that botuline toxin is a ten million times stronger poison than the most toxic dioxin, wether it is made by nature or mankind.
Every material is toxic.
Crude oil itself is toxic, so all from oil derived materials or the use of energy, uses toxic products. The same is true for almost any industry. This is true for chlorine factories and for factories which don't use chlorine, for industrial and for 'natural' products. If that waste is treated accordingly, then it is no problem in either case. There is no reason to treat the toxicity of chlorinated chemicals different from non-chlorinated.