From a letter I received:

警告全部女性 [妻子，女兒，女朋友等等。 ]

Bottled water in your car is very dangerous to women
放在汽車裡的瓶裝水對女性是非常危險的事情﹗ ! !!

This is how Sheryl Crow got breast cancer.
She was on the Ellen show and said this same exact thing.
This has been identified as the most common cause of the high levels in breast cancer、especially in Australia .
這就是謝莉?克羅得乳腺癌的原因。 她在上艾倫的節目裡提到這是千真萬確的事情。這已經被鑑定是罹患乳腺癌裡的高危險因素中最常見的原因了，尤其是在澳洲地區。

A friend whose mother was recently diagnosed with breast cancer.
The Doctor told her: women should not drink bottled water that has been left in a car.
有位朋友的母親最近才被診斷出乳腺癌。 醫生告訴她︰婦女實在不應該喝留放在汽車裡的瓶裝水。

The doctor said that the heat and the plastic of the bottle have certain chemicals that can lead to breast cancer.
So please be careful and do not drink bottled water that has been left in a car、and、pass this on to all the women in your life.
This information is the kind we need to know and be aware of and it just might save a life.
這醫生還說熱能和塑膠瓶子兩者遇在一起就會產生化學物質, 而那些將會導致人們罹患乳腺癌。因此請小心並且千萬不要喝留放在車子裡頭的瓶裝水. 請把這信息傳遞給你生命中的所有女性親友。這是一則或許可以拯救一個生命的訊息, 我們不只應該知道, 而且要多加小心.

The heat causes toxins from the plastic to leak into the water and they have found these toxins in breast tissue.
Use a stainless steel Canteen or a glass bottle when you can!!!
熱能釋放出塑膠裡的有毒物質後,這些物質就滲入到了水裡頭，而人們的胸部組織裡頭竟然就發現了這種毒素。所以如果可以的話，切記改用不鏽鋼杯或是玻璃瓶都好! !

As usual, I go online and find evidence.  I found this: Don’t Drink Bottled Water Left in Car–Urban Legend.

So it is an urban legend.  FDA and other agencies established that the chemical released from plastic bottles through heat is minuscule and will not cause harm to people.

Plus, Sheryl Crow, who had talked about her breast cancer, did not attribute it directly to plastic bottles.

Therefore, the website awarded this legend an outright “False” status.

However they also note that:

A new European study published this year raises doubts about the safety of disposable water bottles… Researchers in Germany found evidence of a man-made estrogen-like compound leaching into water packaged in polyethylene terephthalate (PET) bottles.

Such chemicals, known as “endocrine disruptors,” have the potential to inferfere with estrogen and other reproductive hormones in the human body. However, the authors of the study say more research is required to determine whether, or to what degree, this poses an actual health risk to humans.

For one thing, I don’t like drinking bottled water, because they are just the same as tap water. (In NorCal the tap water is so good, SoCal water always taste weird)  And regardless of whether the bottle leaks chemical or not, I tend to finish the whole bottled water in 1 go, because otherwise the water inside will start to smell (the bacteria in mouth go into water bottle).

Furthermore, no evidence now attributing to the relation doesn’t mean there is no relation between these water bottles and cancer.  By all means, we know nothing about cancer until recent years.  So before the discovery there is no cancer?  I understand this is a very loose analogy, but you get the point.

Anyways, regardless of whether plastic bottle really releases carcinogenic substances, let’s not forget plastic goods are one of the biggest headache of our planet.  Plastic degrade so slowly, that even the plastic bag you use today will outlast all of human race! (we all die, even our descendants all die, and the bag is still here…)

We have already created and dumped so much plastic, that there is a large patch of ocean with absolutely no fish in it on the Pacific (link)

the area is filled with something besides plankton: trash, millions of pounds of it, most of it plastic. It’s the largest landfill in the world, and it floats in the middle of the ocean.

This reason alone is enough for us to really reconsider our consumption habit and lifestyle…

But it’s always like that… If the action only affect something remotely related to us, we won’t really care…  Even if it is related to us, we won’t care as long as there are people saying it’s ok… (I’m thinking those who say global warming is a fake and Al Gore is a joke)

When will we wake up?  Do we really need to see the end before we know the end is coming?