But I read that the student’s project found carcinogens?
The student’s thesis incorrectly identifies di(2-ethylhexyl) adipate (DEHA), a plastics additive, as a human carcinogen. DEHA is neither regulated nor classified as a human carcinogen by the U.S. Occupational Safety & Health Administration, the National Toxicology Program or the International Agency for Research on Cancer, the leading authorities on carcinogenic substances.
In 1991, on the basis of very limited data, the U.S. Environmental Protection Agency classified DEHA as a "possible human carcinogen." However, in 1995, EPA again evaluated the science and concluded that "...overall, the evidence is too limited to establish that DEHA is likely to cause cancer."
Further, DEHA is not inherent in PET as a raw material, byproduct or decomposition product. DEHA is a common plasticizer that is used in innumerable plastic items, many of which are found in the laboratory. For this reason, the student’s detection of DEHA is likely to have been the result of inadvertent lab contamination. This is supported by the fact that DEHA was detected infrequently (approximately 6% of the samples) and randomly, meaning that the frequency of detection bore no relationship to the test conditions.
Moreover, DEHA has been cleared by FDA for food-contact applications and would not pose a health risk even if it were present.
Finally, in June 2003, the Swiss Federal Laboratories for Materials Testing and Research conducted a scientific study of migration in new and reused plastic water bottles from three countries. The Swiss study did not find DEHA at concentrations significantly above the background levels detected in distilled water, indicating DEHA was unlikely to have migrated from the bottles. The study concluded that the levels of DEHA were distinctly below the World Health Organization guidelines for safe drinking water.
Is it true that the U.S. Food and Drug Administration (FDA) only allows plastic beverage bottles, such as those made with polyethylene terephthalate (PET), for one-time use?
No, FDA allows PET to be used in food-contact applications, including food and beverage packaging, regardless of whether the packaging is intended for single or repeated use. PET beverage bottles sold in the United States are designed for single use for economic and cultural reasons, not because of any safety concerns with PET.
In fact, refillable bottles made with the same PET resin as single-use bottles are safely reused in a number of other countries. The only difference is that refillable bottles have thicker sidewalls to enable them to withstand the mechanical forces involved with industrial collection and commercial cleaning and refilling operations.
Can freezing a PET beverage bottle cause dioxins to leach into its contents?
This is the subject of another e-mail hoax. There simply is no scientific basis to support the claim that PET bottles will release dioxin when frozen. Dioxins are a family of chemical compounds that are produced by combustion at extremely high temperatures. They can only be formed at temperatures well above 700 degrees Fahrenheit; they cannot be formed at room temperature or in freezing temperatures. Moreover, there is no reasonable scientific basis for expecting dioxins to be present in plastic food or beverage containers in the first place.