The bill would require that all products or food containers designed for children 3 years and younger contain only trace amounts of the chemical, bisphenol A.
There is little dispute that bisphenol A can disrupt the hormonal system, but scientists differ on whether the very low amounts found in food and beverage containers can be harmful.
The National Toxicology Program, a partnership of federal health agencies, said in a recent draft report that there is "some concern" that the chemical can cause changes in behavior and the brain, and that it may reduce survival and birth weight in fetuses. The conclusion was based on animal studies.
However, the Food and Drug Administration's associate commissioner for science, Dr. Norris Alderson, told Congress in June that there was no reason for consumers to stop using products that contain the chemical.
Despite the uncertainty, consumer concern has prompted some governments and retailers to act.
Congress is considering legislation to ban it in children's products, and Canada has announced it intends to ban the use of the chemical in baby bottles.
Wal-Mart Stores Inc. and Toys "R" Us Inc. say they will stop selling baby bottles made with the chemical next year, and the maker of the hard-plastic Nalgene water bottles announced in April that it would stop using the chemical.
At least 11 other states have considered bills to restrict it.
California's bill was approved earlier this year by the state Senate and it is awaiting a vote by the Assembly. It's not yet clear whether Gov. Arnold Schwarzenegger will sign it if the Legislature sends it to him.
The bill's author, state Sen. Carole Migden, said California is simply following in the footsteps of retailers that are voluntarily pulling products from store shelves.
"I think manufacturers who make money should do all they can to make their products safe," said Migden, D-San Francisco. "This is just one step. It ought to be banned for everything."
Bisphenol A is found in dental sealants, the linings of food cans, CDs and DVDs, eyeglasses and hundreds of other household goods. The chemical industry, grocery retailers, bottled water companies and food processors say it has been used safely for more than 50 years.
A spokeswoman for the canned goods industry said the California bill is vague and could lead to unintended consequences. It could lead to a blanket ban on some canned foods, since their containers often have bisphenol A in their linings, and parents might blend the contents to feed infants, said Colleen Coghlan, spokeswoman for the Washington, D.C.-based Can Manufacturers Institute, which opposes the bill.
The American Chemistry Council also has been lobbying against it. "Many common, everyday products could disappear from grocery stores all across California," says a mailer sent out by the council.
Migden responded to the advertising blitz by amending her bill to emphasize that food and beverage containers designed for the general population would not be affected.
She said only manufacturers of baby food and beverages intended for young children would have to reduce the chemical in their packaging to 0.5 parts per billion by 2012, a standard now being met in Japan. Baby bottles and cups could have just 0.1 parts per billion or less of the chemical beginning Jan. 1.
None of the bills considered in 11 other states has passed so far, said Scott Hendrick, a policy associate at the National Conference of State Legislatures who is tracking the legislation.
In Maryland, a bill by Del. James Hubbard stalled in committee after what supporters described as heavy lobbying from the chemical industry. "I think they've been discredited now," Hubbard said, referring to opponents.
The Minnesota Legislature came close to approving a bisphenol A ban this year as part of a broader chemical bill. Bisphenol A was removed from the legislation after Gov. Tim Pawlenty expressed reservations, said Lindsay Dahl, coordinator of Health Legacy, a coalition of public health groups based in Minnesota. Pawlenty eventually vetoed the slimmed-down version of the law.
Schwarzenegger signed legislation last year banning a common chemical known as phthalates in baby products and toys. But he told lawmakers at the time that a "product-by-product" ban was not the most effective way to craft state policy on potentially unsafe chemicals.
The Schwarzenegger administration created a "green chemistry" initiative in 2007 to study how California should regulate chemicals, an approach favored by industry and many scientists.
Megan Schwarzman, a San Francisco family physician and research scientist at the University of California, Berkeley, endorses Schwarzenegger's comprehensive approach. But she says bisphenol A should be restricted immediately because of its potential effects on children.
"We should definitely take steps to limit our exposure to the substance," Schwarzman said. "Anything we can do to reduce bisphenol A could potentially have big payoffs to protecting human health."