March 30, 2012 -- The U.S. Food and Drug Administration announced today that it won't ban bisphenol A (BPA), the controversial chemical that is widely used in food packaging.

The agency rejected a petition by the Natural Resources Defense Council (NRDC) that called for a ban on BPA as an ingredient in food packaging saying in a statement the council didn't have the scientific data needed for the FDA to change current regulations on the chemical.

But the FDA stressed it would continue to review the safety of BPA.

In response to the FDA's rejection of its proposal, the NRDC told ABCNews.com in a statement the agency "made the wrong call."

"BPA is a toxic chemical that has no place in our food supply," said Dr. Sarah Janssen, an NRDC senior scientist. "The agency has failed to protect our health and safety -- in the face of scientific studies that continue to raise disturbing questions about the long-term effects of BPA exposures, especially in fetuses, babies and young children."

The FDA had agreed to respond by March 31 to a petition filed by the NRDC that called for a ban on BPA as a food additive. The March 31 date was set after the NRDC sued the FDA for not responding to the petition, originally filed in 2008.

The FDA previously said that low levels of BPA are safe, but in Jan. 2010, agreed to "take reasonable steps to reduce human exposure to BPA in the food supply" based on a report from the National Toxicology Program that indicated "some concern" for effects the chemical can have on the brain, behavior and prostate gland of developing fetuses, infants and children, according to the FDA's web site.

Those steps, the agency said, included "supporting the industry's actions to stop producing BPA-containing baby bottles and infant feeding cups for the U.S. market; facilitating the development of alternatives to BPA for the linings of infant formula cans; and supporting efforts to replace BPA or minimize BPA levels in other food can linings."

BPA has been under fire from advocacy groups including the NRDC and the Breast Cancer Fund. The groups claim there is ample evidence linking the chemical to health problems, particularly among fetuses, infants and young children.

Moms Influencing Policy?

Some of the biggest forces behind the drive to ban BPA, however, are not large organizations, but are moms on a mission. They are women using the power of social media to influence policy on an issue they are passionate about.

Dr. Myiesha Taylor of Fort Worth, Texas, started her crusade against BPA about seven years ago. Her two children, she said, were developing vague illnesses and she couldn't pinpoint the cause.

She started doing research to learn about products she may be using or foods her kids were eating that could possibly make them ill.

She happened upon the topic of BPA and was angered by the lack of action toward banning the chemical as well as industry's insistence that data on BPA were inconclusive.

"We can't do human studies. We can't always definitely find a direct answer in a perfectly scientific environment," she said. "There will always be questions, so at some point, we need to use a little common sense -- when multiple studies show a strong association, that's important to consider."

She incorporated her frustrations into her healthy living blog, Coily Embrace, and regularly speaks out.

"As a blogger, you have a community of people interested in what you have to say. We can share news and keep people in the know, and can reach a lot of people," she said. "It used to be so easy for corporations to lobby the government and the media and nobody else had a voice."

Despite numerous concerns, there's still debate over the true effects of BPA on humans. The World Health Organization recently issued a report concluding that although a number of studies found links between low-level BPA exposure and several health effects, including a higher risk for developing mammary tumors in rats and changes in sperm quality in men, "there is considerable uncertainty in this research."

And the authors of a study published in October that found a link between prenatal BPA exposure and the development of behavior problems in children later wrote that "the clinical relevance of these findings is unclear at this point."

LuAnn White, director of the Tulane Center for Applied Environmental Health at the Tulane University School of Public Health and Tropical Medicine, explained that the science the true effects of BPA is tricky.

BPA is one of a class of chemicals that interferes with the actions of hormones in the body, but it's still unclear exactly how these compounds work, White said.

"Laboratory experiments can determine how these chemicals work at the molecular level, but not how that molecular action affects the body since there are so many systems involved," White said. "It's difficult to control for all the possible variables that affect the body."

White said she and her colleagues are cataloguing children's exposures to a variety of chemicals and following them until they are 21, but it will be years until they can have a clearer sense of what BPA does.

She argued that BPA should be removed from consumer products since there is so much uncertainty, but also said that could raise the question of whether food packaging would be more harmful without BPA, and also whether any replacement product is safe. One purpose of BPA is to line the inside of cans, which protects the food inside from being in direct contact with the potentially toxic metals.

The American Chemistry Council called the controversy over BPA a "distraction" back in Feb. and stands by its assertion that the chemical is safe.

"Although governments around the world continue to support the safety of BPA in food contact materials, confusion about whether BPA is used in baby bottles and sippy cups has become an unnecessary distraction to consumers, legislators and state regulators," the council said.

ABC News' Brian Hartman and Katie Moisse contributed reporting.