A large number of academic sources and cancer research organisations have confirmed that there is no evidence to support claims that warming or freezing plastic bottles of water releases chemicals that can lead breast cancer.
Where it all began
Like many other modern day urban legends and scare stories, people have jumped onto an idea to create dramatic and very worrying hype without concern for its actual legitimacy. In 2002, a scientist on a Japanese television show expressed concerns about freezing water in plastic bottles. The opinions of this scientist then flooded the internet through websites and emails. They claimed that freezing, reusing or heating plastic bottles causes the release of chemicals such as DEHA, BPA or dioxins that cause cancer.
Some of the emails claimed that the warnings came from the John Hopkins University in America. This institution does not support these claims and states;
“The Internet is flooded with messages warning against freezing water in plastic bottles or cooking with plastics in the microwave oven. These messages, frequently titled “Johns Hopkins Cancer News” or “Johns Hopkins Cancer Update,” are falsely attributed to Johns Hopkins and we do not endorse their content.”
Walter Reed Army Medical Centre is another institutions falsely credited as a source for this information.
So what about these dioxins?
Dioxins are a group of chemicals that can be released when some types of plastic such as PVC, are burned at very high temperatures. They are sometimes formed unintentionally by industrial processes such as burning fuels and incinerating waste.
One dioxin, known as TCDD, has been shown to cause cancer in people but there is no evidence to support the idea that dioxins are produced when plastics are heated in a microwave oven, as opposed to actually burned in an incinerator. On top of that is not even clear if the plastics used in water bottles or films contain dioxins in the first place.
BPA and DEHA then?
Research by the Food and Drug Administration and the Environmental Protection Agency to date has not found evidence to support a causal link, between BPA and breast cancer.
DEHA is another chemical found in some plastics. Some of the email claims about DEHA are based on the work of an American student who supposedly showed this chemical can migrate from plastic wraps into food at high temperatures. However, once again we find that this substance is not inherent in the plastic used to make these bottles. Even if it was, the U.S. Environmental Protection Agency (EPA) says DEHA “cannot reasonably be anticipated to cause cancer.” and actually removed it from their list of toxic chemicals over a decade ago. The International Agency for Research on Cancer (IARC), confirm that DEHA “is not classifiable as to its carcinogenicity to humans.”
Any more advice from the experts?
Cancer Research states that “It is true that if a plastic bottle is exposed to extremely high temperatures, chemicals in the plastic are released into the water inside. But the amount released would still be within normal safety limits and would not cause any harm.”
Professor Rolf Halden of Johns Hopkins’ Bloomberg School of Public Health also stresses that people should not be afraid of drinking water because of “miniscule amounts of chemical contaminants present in water supply.”
There is no actual evidence to suggest that storing water in plastic bottles is unsafe or that a metal bottle would be any safer. The types of plastic bottles that drinking water is normally sold in are safe to re-use whilst they are still in their original condition and provided that they can be cleaned. Like any object used for food storage, bottled should be cleaned thoroughly with hot, soapy water and dried properly every time they are used, to stop the spread of bacteria.