"FDA assesses the migration potential of plastics and the substances with which they are made. FDA allows food-contact plastics for their intended use based on migration and safety data. The clearance process includes stringent requirements for estimating the levels at which such materials may transfer to the diet. FDA's safety criteria require extensive toxicity testing for any substance that may be ingested at more than negligible levels.
This means FDA has affirmatively determined that, when plastics are used as intended in food-contact applications, the nature and amount of substances that may migrate, if any, are safe."
The issue of chemicals leaching into water bottles is discussed at length by the Snopes Urban Legends site, Bottle Royale.
Bacterial Concerns for All Water Bottles: The real culprits for the safety of reusing any water bottle are the bacteria and fungi that can grow in damp or partially full bottles once they have been opened. These bacteria generally come from your hands and mouth, or any dirt that comes in contact with the mouth of the bottle.
Cleaning Your Water Bottle: Both single-use and reusable water bottles should be thoroughly cleaned and dried between uses. Reusable water bottles generally have wider mouths, making them easier to clean. Dishwashing soap and hot water are acceptable to use for cleaning your water bottle. The risks of bacterial and fungal growth are higher if you use the bottle with a drink that contains sugars. Immediately drain, rinse, and wash your water bottle after your walk if you use it with sports drinks or juices.
Sanitizing Your Water Bottle: If you have visible bacterial slime or mold in your water bottle, you should sanitize your water bottle with a dilute bleach solution of 1 teaspoon bleach and 1 teaspoon of baking soda in 1 quart of water. Allow the solution to sit in the bottle overnight, then thoroughly rinse and dry the bottle before using it again.
What About Lexan Polycarbonate Water Bottles?There are concerns about reusable water bottles made of plastic #7 (Lexan, Nalgene and other clear polycarbonate water bottles) and the possibility that they may leach bisphenol A (BPA). Lexan polycarbonate water bottles have been shown to be safe for use and reuse by the bulk of the research. However, Nalgene and other manufacturers are reformulating their plastic to offer BPA-free water bottles to the public to erase any concerns.
Are Lexan Water Bottles Safe?
Should You Use a BPA-Free Water Bottle?
American Plastics Council "The Safety of Convenience-Size Plastic Beverage Bottles." November, 2003.
Lilya, D. "Environmental Engineering Program." Society for Risk Analysis 2001 Annual Meeting.
"Researcher Dispels Myth of Dioxins and Plastic Water Bottles." Public Health News Center, Johns Hopkins Bloomberg School of Public Health.
International Bottled Water Association. "IBWA Position Statement: Antimony is safe for use in PET plastic." Febuary 9, 2006.
Cleaning Your Water Bottles REI.com