furthermore freeze/thaw cycles will cause the additives to microscopically "bead up" on the surface. then you serve the food out of the freezer bag or tupperware which now contains much of that leachate.   plastic (the pure polymer, not the additives which are always toxic) becomes dangerous in small forms. microplastics as you might have heard the buzzword in the last decade. a small flake of plastic visible to the human eye is not even close, however when the polymer chains are broken by uv rays into bioactive chemicals (in the general size range of enzymes) then we're entering frightening territory because inert things become medicine or poison at this scale, (being allowed to enter cells, binding to receptors, bonding with other fragments floating in solution of your biology and so on.) to summarize: cooking with plastic is bad because of those non-plastic things added to the plastic. it's a personal choice not a problem beyond your waste water and bodies being slightly more contaminated. plastic flakes will increase the amount of toxic shit you are exposed to but they ought to pass almost harmlessly. dangerous to the environment but take decades to be turned into bio active particles. plastic fluff or other manufactured high surface area plastics (99% of our fabrics are plastic so we wash those stray fibers out to sea) is the real danger. these can be broken down by sunlight in a matter of years. a planet killer.
Canada