Nalgene makes the same style of bottles from another type of plastic (UVPE, which, I believe, is HDPE with a UV inhibitor and has no known toxic-chemical issues). Look for the milky white ones; these are the UVPE. They have the same markings on the sides to show you how much you have in there

. As an added bonus, if you're a backpacker, these bottles weigh less than the othehr kind.