For what it's worth, PEX piping is also subjected to some pretty serious safety tests as well. On the flip side, the plumbers who no longer get to charge big bucks for installing copper, oppose PEX, saying it's going to poison you and turn your children green. But don't worry, the people who make the fancy plastics in PEX pipes say there are no problems at all.

Random amusement: our fridge has a fancy activated charcoal filter, which I just replaced. I ran a bunch of water through it to get it all warmed up and such. I find that the straight tap water (via eeeevil PEX piping) tastes better than the water from my fridge (which probably uses its own cheap plastics for the internal piping...).