Did you know that most metal water bottles have a plastic coating inside? You might want to check your water bottle.

Some plastics are safer than others. Here is a quick guide. The big furore right now is over polycarbonate (#7) items, the clear hard stuff used in the newer Nalgenes. The old style (#2) Nalgenes are quite safe. That's the only kind I have, although I have them only for my dog (because they're tough enough that when my dog bashes his pack into a tree or rock the bottles come out unharmed).

I'm not going to carry the weight of metal bottles or give up freezer bag cooking without a lot more hard evidence. On the other hand, I do try to avoid the suspect plastic types.

There are a number of cases in which plastic (such as the plastic lining of food cans) is probably safer than the alternative, which is the acidic food leaching metals out of the cans.

Question--Platypus bottles: The Platypus Hydration website doesn't say what type of plastic the inner liner is, just that it's "food grade," and there are no numbers on the bottles. Does anyone here know what plastic type the liner is? IF nobody here has this info already, I'll try to contact Platypus and post back. Thank you!