I use a Kelly Kettle, so my water is boiling hot, and I like to carry my hot tea with me, so Nalgene Bottles containing BPA are not a safe option, and the safer plastics won't hold up either. I boil my water so I don't bother with filters and all that crap. I have looked again into the Aluminum issue and I feel safe enough with my untreated aluminum Kelly Kettle and with the coated Aluminum Beer Can pots also. Food grade Stainless Steel and Titanium definitely safe, but aluminum is better for the environment. Alzheimer's Association says aluminum is safe enough as long as you don't eat too much processed cheese or pop too many antacids. Yeah the polymer coated beverage cans contain BPA but what can you do? Burn it off? The stuff is everywhere. It contains less than the killer Lexan bottles and that's what counts. If I drank only cold water I might stick with plastic, but I don't, and I just can no longer stand the sight of all the plastic junk we buy everyday. It's everywhere. Yeah some of its durable, but everything is designed to fall apart anyway, and if something is safe and durable they will scare you into recycling it anyways. Bottom line. Buy less plastic.
Consume less. Hike more.