Actually, I read the polycarbonate bottles (also referred to as Lexan, or #7) are the ones that release the toxins when heated.
*sighs* Not this again....
Yes, they can leak an estrogen analog, under very, very specific temperatures (like above 212*F, with the use of a high pressure autoclave or a pressure cooker) or when exposed to very strong detergents (almost drano strength caustics) or certain acids (sufficient that it would be a chemical burn if you got it on you). This whole issue came up because someone was doing some research in a lab and noticed his boy mice never hit puberty. Uproar, ranting, raving, and paranoia ensues. What was happening is that the lab tech that was cleaning the water bottles was throwing them into a high pressure, high temperature autoclave and with the help of an industrial strength detergent (much more than was needed, btw- they should have read the label) was getting the bottle really super clean in a big hurry. Basically, the combination of high temperature and chemical reactions were softening the polycarb and the compound in question was leaching out, in much the same way it does when they soften PVC to the point it is usable as a teething ring (which is no longer legal).
In a nutshell:
-Don't take your PC bottle over the boiling point of water at one atmosphere.
-Don't use lye or other strong caustics to clean your PC bottle.
-Don't use strong acids to clean your PC bottle.
-Don't use abrasives to clean your PC bottle.
That means, no battery acid, no draino, no high pressure steam, no steel wool. But water around 200*F, with dish soap or denture tablets, and a sponge, no risk. If there was, it wouldn't be used for labware, the reason Nalgene got thier rep in the first place is they were the first people to come up with a plastic vial for various medical tests that would be as chemically inert as borosilicate glass. Basically, if you wouldn't put it on/in you, don't put it in/on your water bottle- duh!
Sorry, I've just been hearing this bit of trivia for years. It's like panicking over oxygen di-hydride; yes, that stuff will kill you, easily, and it destroys rocks and metal, but it's only water.
The problems I've found with the HDPE bottles is that they aren't as squash proof (I might have killed one once by sitting on it), and they do take odors and tastes in much the same way a hydration bladder will.