The main point of this article is to point out the dangers of using plastic bottles for water - whether it be store-bought plastic bottles of water, or reusable bottles that you carry around, or the kids take to school or those which you keep in the car.
No plastic bottles or containers are safe! They ALL contain toxic chemicals which have been proven to leach into the water (or foods) they contain. It doesn't matter if the plastic is BPA-free, PET, Tupperware or anything. They all leach chemicals into the water, and 50 times more so when they are hot, which is just one reason why you should never use plastic containers in the microwave oven... The chemicals which leach from plastic containers include hormone-disrupting chemicals and cancer-causing chemicals. So you don't want them in your water or food!
If you can try this experiment - put a 1/2 filled plastic bottle of water in your car and leave it there all day in the sun. Then take off the lid and smell the water - it will smell a lot of chemicals. DON'T drink it! In fact, once a bottle has been left in a hot car or in the sun, it should be thrown away. And yes I believe this applies to refillable water bottles which children take to school for the same reason - they get hot in summer and leach chemicals which can affect their health.
There was a problem with BPA plastic a few years ago, proven to disrupt hormones and cause cancer, then this was replaced by BPA-free or BPS plastic... which sure enough after a few years, was shown to have exactly the same issue. No plastic bottles or containers are safe for hot foods or hot conditions. BUT, it has been shown that freezing water or foods in plastic containers has a similar effect.
And let's not forget the environmental damage of all those plastic bottles...
So what bottles should you use?!
For children, stick to stainless steel bottles for their durability. Yes they mostly have plastic lids, but this usually isn't in contact with the water if standing upright. For adults, use stainless steel or glass containers, perhaps with a neoprene or silicon cover to protect it.
Be "water-safe" this summer! Drink plenty of good filtered water, and store it safely too!