So is BPA -- the controversial, much-debated chemical that, right now, is almost surely lurking somewhere inside a can in your kitchen cabinet -- dangerous? Or is it safe?

Scientists can't come to agreement. Nor can regulators. Nor, unsurprisingly, can corporate America.

Fact is, it's a daunting job for companies to figure out how to deal with BPA, as recent events at General Mills and The Coca-Cola Co. show. General Mills inched away from the chemical, by agreeing to keep it out of its Muir Glen brand of organic tomatoes. By contrast, Coca-Cola opposed a shareholder resolution asking the company to report on its plans to deal with BPA. The resolution got 22 percent of the vote at Coke's annual meeting last week.

While the science of BPA remains clouded, there's growing evidence that consumers aren't willing to wait around for a decisive verdict from the lab. So smart companies at the very least should explore alternatives.

As Rich Liroff of the Investor Environmental Health Network wrote recently in a guest post here:

smart companies will change the way they communicate about BPA and as well as search for alternatives to better align themselves with consumer concerns. Some companies could gain reputational benefits and free media attention from supporting proposed legislation restricting use of BPA.

The IEHN supported the Coca-Cola resolution on BPA.

Some background for readers who haven't followed the debate: Bisphenol A is a chemical that's widely used in products ranging from plastic water bottles to eyeglass lenses. As I wrote (How Wal-Mart Became The New FDA) back in 2008:

BPA is everywhere, used to make polycarbonate, a rigid, clear plastic for bottles, bike helmets, DVDs and car headlights. It's also an ingredient in epoxy resins, which coat the inside of food and drink cans. About 93 percent of Americans tested by the Centers for Disease Control had the chemical in their urine.

Since then, the debate over BPA has only intensified. Canada and Denmark have banned the chemical's use in baby bottles, toys and other products for infants. Regulators in Japan and the EU looked at the evidence and decided that the chemical is safe. The U.S. Food and Drug Administration said in January that it had "some concern about the potential effects of BPA on the brain, behavior and prostate gland of fetuses, infants and children," and that it would join other federal agencies in studying the chemical in both animals and humans.

In the meantime, some companies have paid a heavy price for their use of BPA. SIGG, the Swiss maker of shiny aluminum bottles, got into hot water last year when it got caught using BPA.

Until recently, General Mills assured consumers that they had nothing to fear from BPA, calling it a "critical component" of the coatings inside its cans. Here's how the company responded in December to a customer inquiry, as reported by the La Vida Locavore blog:

Thank you for contacting Muir Glen regarding bisphenol A in food packaging. Bisphenol A is a critical component of protective coatings used with metal food packaging and provides important quality and safety features for canned foods.Scientific and government bodies worldwide have examined the scientific evidence and consistently have reached the conclusion that BPA is not a risk to human health. Recent examples include comprehensive risk assessments in Japan and Europe and a review by an independent panel of experts organized by the Harvard Center for Risk Analysis. The can coatings used in Muir Glen packaging comply with the U.S. Food and Drug Administration requirements for use in food contact applications. These coatings have long played an essential part in food preservation, helping to maintain wholesomeness, nutritional value, and product quality.

We work closely with our suppliers to ensure that all of the food ingredients and packaging materials we use are fully in compliance with U.S. Food and Drug Administration requirements and meet our high quality standards.

We will continue to monitor this situation. If you have any further questions, please feel free to contact us. Your questions and comments are always welcome. For more information on the safety of metal food containers, the U.S. Food and Drug Administration press office may be contacted at (301) 430-2335.
Sincerely,
Brent Taylor

But in its new 2010 corporate responsibility report [PDF], after saying that "General Mills continues to believe that BPA is safe," the company announced a shift:

Viable alternatives have not yet been identified for all types of foods, including some of the packaging applications used by General Mills, but we are optimistic that safe and viable alternatives may be identified in time. For example, one alternative has proven safe and viable in our processing of tomatoes -- and General Mills will transition to can linings that do not use BPA on our organic Muir Glen tomato products with the next tomato harvest.

After I emailed General Mills to ask why, spokeswoman Heidi Geller replied by email:

We made this decision because we know that some of our consumers would like us to pursue alternatives. We have been working with our can suppliers and can manufacturers to develop and test alternative linings that do not use BPA for some time.

So why just organic tomatoes? Because "viable alternatives have not been identified for all types of foods," she wrote.

Still, some companies are evidently working harder than others to eliminate BPA. Eden Foods says it has eliminated BPA from all its cans of organic beans and chili, while noting on its website that BPA-free cans cost about 14 percent more than those with the chemical.

Over at Coca-Cola, meanwhile, the shareholder resolution asking for a BPA study won over some impressive backers -- not just IEHN, but CalPERS, the big California pension fund, and shareholder advisers RiskMetrics and Proxy Governance. The resolution was introduced by social investment firms As You Sow, Domini Social Investments and Trillium Asset Management.

Coca-Cola said:

All available scientific evidence and testing shows that drinks in aluminum and steel cans are safe. BPA levels in canned beverages are extremely low, and it is physically impossible to consume enough canned beverages to ever approach the daily BPA limit established by leading health authorities, including those in the United States, Europe and Canada.

That may be, but for better or worse, a small but growing number of consumers, some of them stirred up by the scare tactics of environmental groups, have decided to try to avoid BPA.

This makes life tough for corporate decision makers who would prefer to wait around for a scientific judgment. The trouble is, scientists can't even agree on the best way to study the chemical's effects, as this article in Nature reports (PDF), although researchers are now trying to forge a consensus on experimental protocols.

The trouble is, once a chemical gets tagged with the adjective controversial -- including by journalists like me, who don't claim to understand or even to have read the science -- it's very hard to put the toothpaste back in the tube, or, in this case, the tomatoes back in the can. The result? Companies that don't seek out safer alternatives could find themselves trying to catch up those that do.

GreenBiz.com Senior Writer Marc Gunther is a longtime journalist and speaker whose focus is business and sustainability. Marc maintains a blog at MarcGunther.com. You can follow him on Twitter @marcGunther.