The Food and Drug Administration must come up with a decision by March 31 on whether to ban a chemical that’s widely used in the plastics and metal linings of food containers, according to a court settlement reached Wednesday between the agency and the Natural Resources Defense Council.

The NRDC filed a petition in 2008 asking the agency to ban bisphenol A, or BPA, citing a growing body of research that suggests exposure to the chemical might pose serious health risks. When the FDA failed to respond within the time frame required by law, the NRDC sued the agency.

The settlement forces the FDA to take a position on a chemical that has been used for more than four decades to manufacture everything from the cans of liquid infant formula to the coating on grocery store receipts. The agreement, approved by New York Federal Judge Barbara S. Jones, said the FDA must issue a final decision, not a “tentative response.”

For years, the government has maintained that low doses of BPA are safe. But last January, the FDA shifted positions and acknowledged that advances in science have raised “some concern” about the chemical’s health risks. The government is now investing $30 million to conduct research on the topic.

But FDA officials haven’t said much about the topic in the past two years or responded to NRDC’s petition despite reams of alarming data about the health risks posed by BPA, particularly to infants and children, said Sarah Janssen, a senior scientist at NRDC.

“There have been no updates,” Janssen said. “FDA has not been very public or transparent on what they’re doing on BPA. . . . We welcome more science, but there comes a point when you have enough information to make a decision, and in this case, we think that point passed years ago.”

In its petition, NRDC cited research that links BPA to reproductive problems, certain cancers and behavioral problems in children. In October, a government-funded study published in the journal Pediatrics suggested that BPA exposure in the womb could lead to behavioral problems in girls, including anxiety and depression.

The American Chemistry Council, which represents the chemical industry, dismissed Wednesday’s settlement as a “non-event.” The group maintains that BPA is safe and complains that the media is confusing consumers over its health risks. For instance, consumer fears about BPA prompted manufacturers to stop making baby bottles and sippy cups with the chemical.

“The consensus of government regulatory bodies around the world, including the U.S. FDA and the European Food Safety Authority, is that BPA is safe for use in food-contact materials,” said Steven G. Hentges, one of the council’s senior directors.

Scott Faber, a vice president at the Grocery Manufacturers Association, said he expects the FDA’s recent research on this topic to support the industry’s position. “Every other regulatory authority around the globe has concluded that BPA is safe for use in food containers, and we expect FDA will reconfirm this finding.”

FDA officials declined to comment on which way the agency is leaning, except to say that they will make a decision based on the information presented in the petition. But that decision might not be the end-all on the health risks posed by BPA.

“It’s important to note that enduring safety is a continuous process,” said Doug Karas, an FDA spokesman. “New studies are being done all the time. They will continue to be considered and add to the body of knowledge for decisions on BPA.”

Meanwhile, Rep. Edward J. Markey, D-Mass. is pressing ahead with legislation he authored that would rid BPA from all food and beverage containers.