Three brands of polycarbonate baby bottles sold in Canada leached detectible amounts of bisphenol A, a controversial compound that mimics the hormone estrogen.
Testing was conducted by Environmental Defence, a Toronto-based environmental group that issued its findings yesterday, offering the first publicly available information on the seepage of BPA from polycarbonate baby bottles sold in the country.
However, the plastics industry and a major baby-bottle makers insisted that the small amount of bisphenol A leaching from bottles shouldn't worry parents.
Whether minute doses of the chemical are a health threat is at the heart of a major scientific controversy over BPA, with the plastics industry saying that the chemical is harmless, a view disputed by some independent academic researchers who specialize in studying hormones.
Health Canada is reviewing the safety of the chemical, and is conducting tests on what it calls the "migration rates" of BPA from bottles. However, it doesn't plan to release its findings until May, when it completes a safety assessment and will announce whether it considers exposures from plastic bottles and other products a health threat.
Environmental Defence is urging parents to avoid polycarbonate plastic and to shift to alternatives, such as glass and plastics labelled BPA free. "Any parent that is currently using these bottles should get rid of them immediately and spring for the $40 it will take to replace them all," said Rick Smith, executive director of Environmental Defence.
He said parents usually have about four baby bottles, which cost about $10 each.
Environmental Defence tested brand names Gerber, Avent and Playtex polycarbonate baby bottles, checking three from each manufacturer.
The highest levels of the chemical were found after bottles were heated, which the group said was done to try to simulate the effects on the plastic of repeated high-temperature dish washing.
It found all of them released BPA when heated to 80 degrees, although all three of the Gerber bottles and one of the Avent bottles didn't have detectible levels in fluids stored at room temperature.
All the Playtex products leaked BPA, regardless of whether they were heated.
Energizer Holdings Inc., the maker of Playtex bottles, referred questions to a website statement that said "multiple regulatory agencies ... advise us and consumers that the use of polycarbonate plastic bottles is safe and should not cause concern for parents." However, the statement said consumers who don't want to use polycarbonate should consider a line of products it makes that are BPA free.
Manufacturers of Gerber and Avent brands didn't provide comments.
Water in the heated bottles absorbed 4 to 8 parts per billion of BPA, while unheated bottles typically had hundreds of times less. A part per billion is an exceptionally small amount, equal to 1 second of elapsed time over 32 years.
The Arlington, Virginia-based American Chemistry Council, a trade group, said in a statement that BPA from baby bottles "is not a risk to human health at the extremely low levels to which consumers might be exposed." It dismissed concerns as "another plastic baby-bottle scare."
Although bisphenol A is man-made, it has a molecular shape that allows it to occupy estrogen receptors on cells. In living things, estrogen is active in concentrations in the parts per trillion range and even less, about a thousand times lower than the concentrations leaking from the heated bottles, giving rise to the worries held by some researchers that the exposures might be harmful.
Bisphenol A is often identified with the plastics industry's recycling symbol of the number seven, enclosed in a triangle. Besides its use in polycarbonate - the hard, clear, shatterproof plastic that looks like glass - it is also applied in DVDs, helmets, dental sealants and epoxy resins lining the insides of food cans, though consumers generally have no way of knowing which of these items contains the chemical.
Mountain Equipment Co-op, a major sporting goods retailer, yanked polycarbonate water bottles from store shelves last year, pending the outcome of the Health Canada review.
Mr. Smith said retailers who sell baby bottles should follow suit.