The findings of a U.S. government science panel and actions by the Canadian government are prompting major retailers and manufacturers to reconsider selling products containing bisphenol-A, a chemical commonly found in hard plastics and food containers.

On April 15, the U.S. National Institutes of Health's National Toxicology Program (NTP) released a report claiming ingestion of bisphenol-A poses a possible risk to human health. The report says high levels of exposure to the chemical can cause reproductive or developmental abnormalities, such as low birth weight, and may lead to a wide variety of cancers including breast and prostate cancer.

Three days later, the Canadian government announced a proposed ban on bisphenol-A in baby bottles, citing its own study on the chemical. Both the U.S. and Canadian studies found that fetuses and infants are at a higher risk for the adverse health effects associated with exposure to bisphenol-A.

In response, Wal-Mart Canada has already begun to pull from its shelves baby bottles containing the chemical. The retailer also announced it would begin phasing out bottles containing bisphenol-A in its U.S. stores and stop selling them by early 2009, according to The Washington Post.

Nalgene, makers of the ubiquitous translucent water bottles, announced it would stop using bisphenol-A in its products. Baby bottle manufacturer Playtex also said it would phase out the chemical.

Bisphenol-A is an ingredient in hard, polycarbonate plastics. No. 7 plastics, like those used for reusable water bottles, are usually polycarbonate. Bisphenol-A is also an ingredient in certain resins used to line food cans.

The NTP report finds most humans are exposed to bisphenol-A and retain it in their bodies. The report states, "Bisphenol A can migrate into food from food and beverage containers with internal epoxy resin coatings and from consumer products made of polycarbonate plastic such as baby bottles, tableware, food containers, and water bottles." The report cites another U.S. study that found bisphenol-A in 93 percent of humans tested.

The panel then looked at studies of laboratory rodents exposed to bisphenol-A and found a wide variety of adverse health effects at high doses and other possible health effects at low doses.

NTP concluded bisphenol-A is of "some concern" — a qualitative designation. Other options available to the panel included "serious concern" and "concern" for riskier substances, and "minimal concern" and "negligible concern" for less risky substances.

Although the NTP report finds bisphenol-A may pose risks to human health, NTP cannot act on its findings because it is not a regulatory agency. Regulation of the chemical would fall to the U.S. Food and Drug Administration (FDA) which, like NTP, is a division of the Department of Health and Human Services.

FDA has consistently refused to regulate bisphenol-A in the face of public and congressional pressure. The agency has said bisphenol-A does not pose a "safety concern at the current exposure level."

But a congressional investigation uncovered that FDA had relied on two industry-funded studies in making its determination not to regulate. The House Energy and Commerce Committee wrote to FDA in January asking the agency to identify the basis on which it has made its decision. FDA identified two studies, both of which were funded by the American Chemistry Council. One study had never been published or subjected to peer review.

Most other bisphenol-A studies have shown varying degrees of human health risks. In August 2007, an NIH-sponsored panel of 38 independent experts found that the level of bisphenol-A present in the average human's bloodstream is higher than levels that have been found to cause adverse health effects in laboratory tests.

The move by Wal-Mart, Nalgene, and others mirrors that of other industries that have decided to take voluntary steps in response to mounting evidence and public pressure, but in advance of federal mandates. For example, after widespread reporting of the dangerous effects of diacetyl, a chemical used to give popcorn its buttery flavor, major popcorn makers like Orville Redenbacher announced they would discontinue use of the chemical. Countless individual businesses and industries are also taking steps to mitigate their carbon footprints in order to combat climate change.

The trend is a natural response to the Bush administration's refusal to regulate in any area, even when regulation would aid both consumers and businesses. In the cases of both diacetyl and climate change, the Bush administration has rebuffed public petitions, court mandates, and congressional pressures to act.

Most recently, the White House halted a U.S. Environmental Protection Agency (EPA) rulemaking which would have set carbon emissions limits. Instead, EPA is asking for "comment on the best available science." Similarly, FDA and other Bush officials continue to emphasize the need for further study of bisphenol-A's effects before action can be taken.