02/19/2013 02:11 pm ET Updated Apr 21, 2013

Say Goodbye to the Campbell's Soup Can?

Is this the end of the Campbell's soup can?

Today's version of the metal can could be a thing of the past, if a consortium of activist groups gets its way. Their target is a chemical that, if banned, could change the very way food is packaged. But there's a problem. Neither the activist groups nor the food and can companies have any idea what will replace the current metal can if it is outlawed.

The chemical is Bisphenol A, or BPA. The latest battle against it is unfolding in California where, last month, the Office of Environmental Health Hazard Assessment made moves to designate it as a "toxicant" -- a major step toward having it banned in the state. BPA defenders called the effort "scientifically unjustified," but the state agency argued that the use of BPA should be halted because researchers believe animal studies of the substance have produced "evidence of adverse developmental effects" in human beings.

At the heart of the debate, then, is the question of whether or not BPA is safe. National and international groups, like this California state agency, believe that it is not. Others counter that no compelling proof exists that proves it is harmful. "Over all," says Julie Goodman of the Harvard School of Public Health, "the weight of scientific evidence indicates that current issues of BPA does not pose a health risk to people, including infants and children."

Only in recent years has BPA come under intense attack, which is surprising since it has been used in an array of products for decades, dating back to the 1960s. Historically, companies have employed BPA as a chemical building block to harden plastic in products as diverse as eyeglasses lenses, sporting equipment, and food and beverage containers. BPA is also used in the coating that lines the interior of virtually all metal cans to keep food and beverages safe from corrosion and germs. The substance has become so popular that today it is present in thousands of products.

Even though BPA was used for years without question, researchers began examining it about a decade ago, producing hundreds of studies. In 2010, in a study published in the journal Fertility and Sterility, researchers found that when a group of Chinese factory workers were exposed to BPA they had lower sperm counts and inferior sperm quality. In a Paris-based study, researchers determined that if fetal testicles are soaked in BPA they produce less testosterone. In these and similar studies, scientists were trying to prove a widely held assumption that BPA acts as an "endocrine disruptor." This means that exposure to it has a debilitating effect on the reproductive system, the worst of the maladies critics claim it causes.

"While you may likely find hundreds of studies on BPA," says Steven G. Hentges of the American Chemistry Council, "many use novel approaches or are of limited relevance to human exposure. Perhaps most relevant to actual, real-world safety is the recent research funded by the Environmental Protection Agency [which] indicates that, because of the way BPA is processed in the body, it is very unlikely that it could cause health effects at any realistic exposure level."

Specifically, the EPA study found that the human body excretes BPA through urine with such efficiency that, to quote one source, "it is very unlikely BPA could cause health effects." Other organizations concur. In 2010, the World Health Organization announced that, based on available research, "initiation of public health measures [concerning BPA] would be premature." In 2012, Food Standards Australia New Zealand concluded that "the weight of scientific evidence indicates that exposure to BPA in food does not present a significant human health and safety issue." That same year, the Food and Drug Administration said that "the scientific evidence at this time does not suggest that the very low levels of human exposure to BPA through the diet are unsafe."

Nevertheless, opponents of BPA point to studies supportive of their position and lately have achieved stunning success. In 2010, the government of Canada labeled BPA "toxic." The government said it did so to "meet society's expectations." With such a designation, Canada could ban BPA. "We are literally marinating in [BPA] on a minute-by-minute basis," said Environmental Defense executive director Rick Smith, evaluating the risk he believed BPA poses to the public.

After the victory in Canada, advocacy groups in America petitioned the FDA to ban the use of BPA in sippy cups and baby bottles, pointing to research suggesting that young children and infants may be especially susceptible to BPA. Then, last year, the Senate in France approved a ban on BPA scheduled to begin in July 2015. These developments informed the efforts in California to have BPA banned there. Of course, a ban would mean that products containing the substance would be eliminated in the state, just as they will be in France in 2015.

Does this spell an end to the metal can? If so, how will millions of Americans get access to the food that currently comes in cans -- beer, tuna, soup, vegetables and the like? Of paramount concern is the fact that the BPA-informed lining helps keep food safe and fresh longer, which is why it is there in the first place.

"Any legislative ban not based on the science would jeopardize the food supply to some extent," says John M. Rost of the North American Metal Packaging Alliance, "whether it leads to shortened shelf life and greater food waste, or the potential for increased food-borne illnesses. Either way, an unjustified ban will have an impact on consumers."