Ryan, i'm no scientist and i have no idea how many times you could theoretically reuse a single-use plastic container before it begins to break down and emit the stuff we're concerned about. we've switched to glass or ceramic containers for on the go drinks and food storage, so for me there's no need to debate the safety of plastics. i just don't use 'em unless there's no alternative.
but i found this, which has been widely re-printed so i don't know the origin...it sums up what i've read elsewhere succinctly, though. hopefully it's helpful to you.
Plastic water bottles are very convenient for carting water around when we are on the go, as they don't break if we drop them. However, it is worth paying attention to the type of plastic your water bottle is made of, to ensure that the chemicals in the plastic do not leach into the water. If you taste plastic, you are drinking it, so get yourself another bottle.
To be certain that you are choosing a bottle that does not leach, check the recycling symbol on your bottle. If it is a #2 HDPE (high density polyethylene), or a #4 LDPE (low density polyethylene), or a #5 PP (polypropylene), your bottle is fine. The type of plastic bottle in which water is usually sold is usually a #1, and is only recommended for one time use. Do not refill it. Better to use a reusable water bottle, and fill it with your own filtered water from home and keep these single-use bottles out of the landfill.
Unfortunately, those fabulous colourful hard plastic lexan bottles made with polycarbonate plastics and identified by the #7 recycling symbol, may leach BPA. [Thug note: Nalgene also offers a BPA-free #2 plastic version, so check yours before tossing it out.] Bisphenol A is a xenoestrogen, a known endocrine disruptor, meaning it disturbs the hormonal messaging in our bodies. Synthetic xenoestrogens are linked to breast cancer and uterine cancer in women, decreased testosterone levels in men, and are particularly devastating to babies and young children. BPA has even been linked to insulin resistance and Type 2 Diabetes. For more of the science on the effects of BPA on our endocrine system etc. see these studies: Environmental Health Perspectives Journal. Nalgene, the company that manufactures the lexan water bottles also makes #2 HDPE bottles in the same sizes and shapes, so we have a viable alternative. Order one at Nalgene.
Unfortunately, most plastic baby bottles and drinking cups are made with plastics containing Bisphenol A. In 2006 Europe banned all products made for children under age 3 containing BPA, and as of Dec. 2006 the city of San Franscisco followed suit. In March 2007 a billion-dollar class action suit was commenced against Gerber, Playtex, Evenflo, Avent, and Dr. Brown's in Los Angeles superior court for harm done to babies caused by drinking out of baby bottles and sippy cups containing BPA. So, to be certain that your baby is not exposed, use glass bottles.
Check the recycling numbers on all your plastic food containers as well, and gradually move to storing all food in glass or ceramic.
Store water in glass or brass if possible, and out of direct sunlight.