Disposable water bottles
You may have seen e-mails or websites that say disposable plastic water bottles cause cancer if they're frozen, or left in the car and exposed to heat. These rumours are not true.
Disposable water bottles are generally made of a plastic known as PETE or PET (polyethylene terephthalate). Recycling codes help identify different plastics from each other and make recycling more efficient. PETE plastics can usually be identified by the raised recycling mark containing a “1” on the bottom of the item. See the American Chemistry Council for a description of recycling codes.
Some versions of the rumour incorrectly say that cancer-causing substances known as dioxins leach from the bottles.
Dioxins are a group of highly toxic substances that are known to cause cancer. However, there is no evidence that plastic water bottles contain dioxins.
Some plastics contain substances known as “plasticizers” to make the plastic more flexible and less brittle. DEHA is one common type of plasticizer. Most of the rumours say that the disposable plastic water bottles leach DEHA, but incorrectly call it diethylhydroxylamine - another substance sometimes used in plastics. Neither substance is suspected of causing cancer.
Canadians should be aware that re-using disposable plastic water bottles can be harmful if they are not cleaned and dried properly or if they're left in warm areas - this can allow harmful germs to grow. These germs can make people sick if ingested, causing vomiting or diarrhea. This is true with other types of containers, not just disposable water bottles. However, there is no evidence that re-using disposable plastic water bottles can cause cancer.
For more information
Health Canada – The Safety of Bottled Water
Microwaves and plastic containers
Bisphenol A and reusable plastic water bottles