If low prices and a sluggish market were not enough to depress polycarbonate (PC) producers, fallout from the latest North American studies on the influence of feedstock bisphenol A (BPA) on human health may be. Reports that the Canadian health authority, Health Canada, could label bisphenol A “toxic” or “dangerous” have prompted calls for a ban on the use of PC in popular reusable drinking water bottles because of suggested leaching of bisphenol A into the liquid. Some Canadian retailers already have provisionally removed the bottles from their shelves and media blogs have been clogged for days with discussions of the issue.

Health Canada began evaluating BPA last year as part of a study of 200 chemicals. Reports on 15 April 2008 suggested that health minister Tony Clement could announce a conclusion imminently, but also that this might not come before the end of May. If Canada does declare the feedstock to be toxic or dangerous, it will not necessarily be banned or restricted – which would spell an end to the use of polycarbonate in food packaging. It could just as easily advise yet more research. By that time, the country’s retail sector, however, may have resolved the issue itself. As Clement noted, ”retailers make their own decisions on what they think will sell and won’t sell.”

Simultaneously, a draft report from the National Toxicology Program (NTP) of the US Department of Health and Human Services also was making waves, even though it stated only that it had “some concern” and “no direct evidence” about BPA’s effect on humans or their unborn children. NTP, part of the National Institute of Environmental Health Sciences (www.niehs.nih.gov), pointed to the absence of conclusive studies with humans, especially as regards dosages below 5ppm. The report, based mainly on previous scientific evaluations and itself subject to a peer review did say that there appeared to be “clear evidence” of adverse effects on the reproductive systems of rats.

In its own previous studies, the US Food and Drug Administration (FDA), although criticised by some as leaning too much on the conclusions of industry, has given the PC feedstock a clean bill of health. The American Chemistry Council (ACC) said the results of the NTP’s “rigorous scientific evaluation process” affirmed that “there are no serious or high level concerns” about human exposure to BPA. It planned to hold a press conference on 17 April 2008, to counter negative news reports.

If Health Canada does label BPA toxic or dangerous, it would be the first public authority worldwide to do so. Such moves are being discussed in several US states, including California, and also are on the agenda of some city councils.

What most of the public discussion has ignored thus far is that – whether there is leaching or not – the amount of polycarbonate used in food packaging is actually negligible. According to the polymer’s largest producer, Bayer MaterialScience (BMS, Leverkusen / Germany; www.bayerbms.com), only around 3% of the 3m t annual global PC output goes into packaging, and not all of this is for food. By far, the largest applications are optical storage media (32%) and E&E (23%).

e-Service:
Draft NTP report on bisphenol A by the National Institute of Environmental Health Sciences as a PDF document (543 KB)


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