In recent years, studies have suggested that polycarbonate plastics such as the ones Nalgene used may leach endocrine disruptors.[5] Nalgene denies that the quantity leached from their products posed a significant threat to health.[5] Among the secreted chemicals, Bisphenol A (BPA) is a concern as it binds to estrogen receptors, thus altering gene expression.[6][7][8] Other research has found that fixatives in polycarbonate plastics can cause chromosomal error in cell division called aneuploidy. Nalgene claims these chemicals are only potentially released from Nalgene products when used at temperatures outside of the designed range.
stolen from wiki.
But seriously i think anything these days CAN cause harm if used incorrectly.
I would stick to metal or glass not sure if alcohol will "leech" anything