Correct me on where I’m wrong, but isn’t this already the case in re toxic waste? At one point in the distant past, near as I can tell, it was legal to just pour this nasty stuff out….where ever. (Example Hudson River PCB’s) And then, the Superfund law, etc was passed and made this retroactively illegal and asserted liability, both civil and possibly criminal, for past actions that weren’t previously prohibited.

I have a difficult time wrapping my head around retroactive liability and the clear and plain prohibition in the Constitution of ex post facto law.