The Dangers of Using Plastic Bottles
Most types of plastic bottles are safe to reuse at least a few times if properly washed with hot soapy water. But recent revelations about chemicals in Lexan (plastic #7) bottles are enough to scare even the most committed environmentalists from reusing them (or buying them in the first place). Studies have indicated that food and drinks stored in such containers—including those ubiquitous clear Nalgene water bottles hanging from just about every hiker’s backpack—can contain trace amount of Bisphenol A (BPA), a synthetic chemical that interferes with the body’s natural hormonal messaging system.
The same studies found that repeated re-use of such bottles—which get dinged up through normal wear and tear and while being washed—increases the chance that chemicals will leak out of the tiny cracks and crevices that develop over time. According to the Environment California Research & Policy Center, which reviewed 130 studies on the topic, BPA has been linked to breast and uterine cancer, an increased risk of miscarriage, and decreased testosterone levels. BPA can also wreak havoc on children’s developing systems. (Parents beware: Most baby bottles and sippy cups are made with plastics containing BPA.) Most experts agree that the amount of BPA that could leach into food and drinks through normal handling is probably very small, but there are concerns about the cumulative effect of small doses.
Health advocates also recommend not reusing bottles made from plastic #1 (polyethylene terephthalate, also known as PET or PETE), including most disposable water, soda and juice bottles. According to The Green Guide, such bottles may be safe for one-time use, but reuse should be avoided because studies indicate they may leach DEHP—another probable human carcinogen—when they are in less than perfect condition. The good news is that such bottles are easy to recycle; just about every municipal recycling system will take them back. But using them is nonetheless far from environmentally responsible: The nonprofit Berkeley Ecology Center found that the manufacture of plastic #1 uses large amounts of energy and resources and generates toxic emissions and pollutants that contribute to global warming. And even though PET bottles can be recycled, millions find their way into landfills every day in the U.S. alone.
Another bad choice for water bottles, reusable or otherwise, is plastic #3 (polyvinyl chloride/PVC) , which can leach hormone-disrupting chemicals into the liquids they are storing and will release synthetic carcinogens into the environment when incinerated. Plastic #6 (polystyrene/ PS), has been shown to leach styrene, a probable human carcinogen, into food and drinks as well.

Safer choices include bottles crafted from safer HDPE (plastic #2), low-density polyethylene (LDPE, AKA plastic #4) or polypropylene (PP, or plastic #5). Consumers may have a hard time finding water bottles made out of #4 or #5, however. Aluminum bottles, such as those made by SIGG and sold in many natural food and product markets, and stainless steel water bottles are also safe choices and can be reused repeatedly and eventually recycled.