There used to be a rumor that women can not drink bottled water put in a car because plastic bottle will give off chemical material once meet with thermal energy, and these chemical materials can lead to breast cancer. 

The international bottled water association,(IBWA) and the American Food and Drug Association(FDA) also announced the same statement. Explain that bottled water containers are safe in many circumstances, as to whether it is safe under high-temperature, there is no scientific support. We learn from this matter that people are concerned about the safety of bottled water.
 
So how many exactly kinds of plastic bottle are there? Looking in the supermarket, you can see these icons under plastic water bottles:
 


The first one is the recycling symbol of polyethylene terephthalate, PET, 90 percent of current beverage plastic bottles are made of this material.

Popular saying that PET is harmful to health seems to come from the fear of DEHP, PET has a similar chemical structure as DEHP. But they are different, harmful molecule won’t spread to water, so PET doesn’t bring harm to physical health. It only produces harmful things until when the temperature is considerably higher than temperature in a car in summer.

Although PET won’t break down under daily temperature, micro molecule is still possible to come out; these small molecules may bring potential harm. So manufacturers should pay attention and try to reduce insufficiently reacted micro molecules.

For PET bottles manufactured by standard enterprises, PET bottles are safe even under high temperature in summer.

Besides, we need to notice that some thin bottles made of HDPE has a relatively narrow temperature application, because HDPE will break down under high temperature, leading bottle change its shape. But PP products have a higher temperature resistance than HDPE.

Besides, PC and PP containers are usually used repeatedly, so consumers should pay attention to containers’ cleaning.