The big Arrowhead water bottles (for water coolers) are #7 plastic, which is bad for leaching BPA. On the other hand, most single-use water bottles are made of #1 polyethylene terephthalate (PET or PETE). These bottles, if old, reused or heated, may release two phthalates: Di(2-ethylhexyl adipate), or DEHA, and benzyl butyl phthalate (BBP), which are possible human carcinogens, according to the U.S. Environmental Protection Agency.
You can identify better plastics by the recycling code numbers stamped in them. Look for reusable bottles made of:
#2 (HDPE, high-density polyethylene, the most widely recyclable), #4 (LDPE, low-density polyethylene), or #5 (PP, polypropylene).
These plastics have not been found to release BPA or phthalates.
at 10:47 AM on Aug. 10, 2010