It was the first City Council committee meeting in memory that included presentations about heat-labile molecular bonds and synthetic estrogen.

But beyond the crash course in chemistry and physiology, the license and finance committees set a more significant precedent Tuesday when they heard testimony on a proposal that could make Chicago the first place in the country to restrict the sale of products containing bisphenol A, a widely used chemical that’s been linked to a range of health problems.

“I can’t tell you, as a parent of a two-year-old, how dismayed and aghast I was to discover that we may have unwittingly exposed our child to a dangerous product,” said First Ward alderman Manny Flores, who sponsored the ordinance with Finance Committee chairman Ed Burke. “I’m not the only father out there, and I’m not the only mother out there, who’s concerned about this.”

Flores may not be a mother at all, but he may be right to be wary of BPA, which is found in plastic baby bottles, food can linings, compact discs, and scores of other commonly used products. Last year, as Canada prohibited its use in baby bottles, the U.S. Food and Drug Administration was blasted for brushing off research that suggested BPA could contribute to heart, liver, and prostate problems. Since then additional studies have found that the chemical could be more dangerous and resilient than previously thought, and the FDA is reviewing its earlier conclusion.

Flores said he doesn’t want to waste any more time. “Let the city of Chicago show the FDA how to protect its citizens,” he said.

The ordinance would prohibit the sale of any “children’s product” containing BPA—that is, milk bottles and other goods “intended for use by, or care of, a child seven years or younger.” Manufacturers and retailers that violate the ordinance would face fines of up to $500 per item per day.

Environmentalists and a UIC physiologist testified, sometimes in extraordinary scientific detail, about how BPA can seep into food and enter the human body. “Probably everyone in this room has it in them,” said Max Muller, program director of Environment Illinois.

Several representatives of business groups argued that while the science on BPA is inconclusive the consequences of a ban are quite clear. “We would not knowingly sell products that would cause harm to customers,” said Tanya Triche, an attorney for the Illinois Retail Merchants Association. “But if this were to pass, stores would have to pull scores of products off their shelves in 180 days. Such a move would have a serious financial impact.”

Some aldermen appeared engrossed in and troubled by the science lessons, others not so much. “Mr. Muller, you’re losing your audience,” Burke declared at one point. “We have a lot of witnesses, so you’re going to have to move through this a little faster.”

Burke, however, did argue that the ordinance was critical and historic, comparing it to the city’s 1971 ban on ecosystem-destroying phosphates, which was subsequently copied by other governments across the country. He didn’t note that the phosphates ordinance, like other city environmental regulations, has only been as effective as government has willed it to be; and before the end of the meeting he announced that the BPA proposal would be held for at least a few weeks.

Instead, he and Flores abruptly introduced a nonbinding resolution urging the FDA to act quickly and “take appropriate action.” Burke promised that they’d push the much stronger ordinance again in a few weeks if the feds didn’t make any progress: “We will not hold this ordinance forever.”