Every single retro gaming site i go to mentions it somewhere. If it was perfectly fine and harmless why do comic bags feel the need to advertise stuff like "No PVC Acid Free 25 Per Pack".
"Using PVC (polyvinyl chloride), you'd have a greenish tint on your mags after a couple years (or less, depending on heat and humidity). But polypropylene and polyethylene are chemically inert plastics, and are therefore perfectly safe (plastic food bowls and containers most of the time are polypropylene, and plastic sandwich bags are polyethylene) .
(So I took 2 full years of chemistry in college... .) "
I can look around for more examples if you wish... Feeling kinda lazy right now.