But for years, critics have raised concerns that BPA, which can get into the food, may disrupt hormones in humans and cause other health problems.
In response to consumer pressure, many manufacturers have removed BPA from baby bottles and sippy cups.
Some food companies, including the Campbell Soup Co. in Camden, have started to use alternatives in the linings of cans.
The FDA approved use of bisphenol A in the 1960s. As concerns about its safety accumulated, the agency released a draft report in 2008 finding that it remains safe in materials that could come in contact with food. A subcommittee of its science board raised questions about whether the report had adequately considered the most recent scientific information.
According to the FDA's website, its National Center for Toxicological Research is pursuing a set of studies on the safety of low doses of BPA. "Depending on the results, each could influence regulatory decisions about BPA," the website says.
Meanwhile, BPA is in just about all of us. It's been found in breast milk and umbilical cord blood. The Centers for Disease Control and Prevention, through its studies on human exposure to environmental chemicals, has found BPA in more than 90 percent of urine samples.
Food has been shown to be the biggest source of BPA exposure for most Americans. Many poor people have higher levels because they eat more canned food.
BPA also is used in cash-register receipts, so store clerks and others who handle them also have higher levels.
Thousands of studies have examined its effects.
"The science is complicated, sometimes contradictory, and has obviously ignited a lot of controversy," said Sarah Janssen, a senior scientist with the NRDC.
However, many studies have concluded that BPA disrupts the endocrine system. "Low levels of exposure have been linked to a wide range of health effects," Janssen said, including some cancers.
"The NRDC felt there was enough scientific evidence to conclude that BPA was not a safe chemical and should not be in our food supply," Janssen said.
The industry has maintained that BPA is safe.
"We believe that current can packaging is one of the safest options in the world," said Campbell's chief financial officer, Craig Owens, in a February conference call with shareholders.
"However," he said, "we recognize that there is some debate over the use of BPA. The trust that we have earned from our consumers for over 140 years is paramount to us and we have been monitoring and working on the issue for several years. Because of this, we have already started using alternatives to BPA in some of our soup packaging and we are working to phase out the use of BPA in the lining of all of our canned products."
Different food types may require different substitutes. Acidic foods such as tomatoes, for instance, might require a different lining from peas.
"There's probably not going to be a single alternative that applies across every food company and every product line," Campbell spokesman Anthony Sanzio said.
Nick Morales, a legal expert with the NRDC, said that unless the food agency can prove the safety of the chemical, it must disallow its use. "In other words, if FDA isn't sure whether a chemical is safe or harmful, it can't allow its use."
An FDA spokesman confirmed that the deadline was March 31 but said he did not know specifically when the agency would respond.
Among tips for minimizing the exposure of infants, who are considered to be more susceptible to BPA's effects, the FDA recommends breast-feeding for 12 months, discarding scratched baby bottles and feeding cups, and not putting boiling or very hot liquids into BPA-containing bottles or containers.
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