Don't know if it is still relevant, but I had a search on the net with nalgene lexan products: apparently there are serious health questions being raised with polycarbonate (PC / Lexan) plastic being used for food/drink packaging.
On their website, nalgene give links to scientific reports saying that everything is ok... so no real answer. Might also be a commercial/lobby attack, no idea. But it is not new.
Nalgene propose their products in different types of plastic, the issue is only about lexan, which seems to be the most popular.
Then there are plenty other thing bad for our health, and for this one there is no certainty.... but I definitely don't want to be finding out after 20years of use.

check out your bottles