Polyethylene terephthalate (PET) is popular with beverage manufacturers because it is lightweight and sturdy. A health scare surrounding PET plastic bottles began in 2002, when on a Japanese television program a scientist voiced concern about freezing water in plastic bottles. The scientist’s claims were subsequently distributed in emails and websites which incorrectly state that reusing, heating or freezing plastic bottles releases chemicals which cause cancer called dioxins, or di-ethylexyl adipate (DEHA). Some of the emails credit well known American institutions such as John Hopkins University or the Walter Reed Army Medical Center. However these institutions deny any involvement and do not endorse the content of such emails and websites.
There is no convincing scientific evidence to support the claim that plastic bottles cause cancer. Dioxins are chemicals that are formed during industrial processes such as burning fuels and incinerating waste. It is not clear if plastics used in water bottles contain dioxins and there is no evidence that dioxins are produced when plastics are heated as opposed to burned in an incinerator. DEHA is a chemical found in some plastics, however, there is no evidence that DEHA is present in plastic bottles. Further, after reviewing the available evidence, the International Agency for Research on Cancer (IARC) determined that DEHA and dioxins (except 2,3,7,8-Tetrachlorodibenzo-para-dioxin) cannot be classified with respect to their carcinogenicity (cancer causing properties) to humans. IARC is a part of the World Health Organisation which convenes international expert working groups to evaluate the evidence of the carcinogenicity of specific exposures. Although IARC did classify 2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD) as carcinogenic to humansin 1997, it is important to note that TCDD has never been produced commercially except for scientific research. TCCD is formed as a side product when producing certain pesticides, herbicides, and disinfectants, and therefore does not pose a risk in terms of plastic bottles. It is also important to note that potential health risks from heating plastics requires temperatures substantially higher than temperatures reached inside a car in the Australian summer.
In Australia, manufacturers are required by the Australian New Zealand Food Standards Code, administered by the NSW Food Authority to ensure food packaging materials are safe and meet the requirements of the relevant Standard. The Australia New Zealand Food Standards Code are legislative instruments under the Legislative Instruments Act 2003. Standard 1.4.3, Articles and Materials in Contact with Food, deals with food contact materials in general terms but does not address specific individual packaging materials for food contact or how they should be produced or used. The Standard also refers to the Australian Standard for Plastic Materials for Food Contact Use, providing a guide to industry about the production of plastic materials for food contact use.
This Standard states that is safe to re-use plastic bottles as long as their condition has not deteriorated and they can be cleaned to avoid health risks associated with bacteria growing in them.