Senator Dianne Feinstein of California and Senator Patrick Leahy of Vermont on March 19 introduced the B.P.A. in Food Packaging Right to Know Act that would inform consumers whether the chemical bisphenol-A (B.P.A.) was used in food packaging. Mr. Leahy and Ms. Feinstein partnered in sponsoring a similar bill during the 113th Congress, but the legislation was not enacted. Ms. Feinstein has been a champion of those seeking to ban the use of B.P.A. in food packaging for several years.

B.P.A. is an industrial chemical used to make polycarbonate, a hard, clear plastic, which is used in many consumer products, including drinking bottles. B.P.A. also is found in epoxy resins, which act as a protective lining on the inside of some metal-based food and beverage cans.

The Food and Drug Administration must approve the use of substances that may migrate from packaging into food, including B.P.A. The original approvals for B.P.A. were issued under the agency’s food additive regulations and date from the 1960s. In the intervening years, the F.D.A. has found no science-based evidence that would lead it to change its view that B.P.A. in its currently approved uses poses no health risk.

But public concerns prompted by various studies asserting B.P.A. may have serious adverse health effects resulted in congressional efforts to limit or even ban its use in food packaging.

The Feinstein-Leahy bill would require food packaged with B.P.A. to have a label that reads as follows: “This food packaging contains B.P.A., an endocrine-disrupting chemical, according to the National Institutes of Health.”

“Consumers deserve to know if the items they frequently purchase at the grocery store could expose them and their families to B.P.A.,” Ms. Feinstein said. “This straightforward bill would simply require packaging that contains B.P.A. to be labeled, so consumers can make the best decisions for their families.”

Mr. Leahy added, “Vermont already has acted to ban many B.P.A. food and drink containers in 2010 after health experts and scientists — including through the National Institutes of Health — identified the potential harmfulness of these chemicals. I firmly believe in the right of consumers to make informed choices. Knowledge is empowering, and knowledge about B.P.A. ingredients can also stimulate further reforms by the marketplace. I am proud to join Senator Feinstein in introducing a bill that will ensure that consumers are better informed about the products they buy.”

Passage of the bill would not affect the right of a state, political subdivision of a state, or Indian tribe, “to adopt or enforce any regulation, requirement, liability, or standard of performance that is more stringent than the regulation, requirement, liability, or standard of performance under this section or that applies to a product category not described in this section; or requires the provision of a warning of risk, illness, or injury associated with the use of food containers composed, in whole or in part, of bisphenol-A.”

In addition to labeling packaging containing B.P.A., the Feinstein-Leahy bill would require no later than 180 days from enactment, the Secretary of H.H.S. “shall issue a revised safety assessment for food containers composed, in whole or in part, of bisphenol-A, taking into consideration different types of such food containers and the use of such food containers with respect to different foods, as appropriate.”

Through this process, the H.H.S. “shall determine whether there is a reasonable certainty that no harm will result from aggregate exposure to bisphenol-A through food containers or other items composed, in whole or in part, of bisphenol-A, taking into consideration potential adverse effects from low dose exposure, and the effects of exposure on vulnerable populations, including pregnant women, infants, children, the elderly, and populations with high exposure to bisphenol-A, including workers who are exposed through production practices or handling of final products.”

The bill also would require alternatives to B.P.A. to be evaluated in the same way.

The bill was endorsed by the American College of Obstetricians and Gynecologists, the American Nurses Association, the American Public Health Association, the Breast Cancer Fund, the Center for Science in the Public Interest, Consumers Union, the Environmental Working Group, the Endocrine Society and Women’s Voices for the Earth.

On its part, the F.D.A. noted in the fall of 2014 it completed a four-year review of more than 300 studies on B.P.A.

“The F.D.A. review has not found any information in the evaluated studies to prompt a revision of F.D.A.’s safety assessment of B.P.A. in food packaging at this time,” the agency noted.