Support for this article was provided by the Investigative Fund of the Nation Institute.

Do you let your baby girl smoke cigarettes in her crib? Do you allow your son to light up in his stroller, after a tough morning at daycare? Do you nurse your child while puffing on a Marlboro Light?

If not, you may be interested in what’s happening in a few top research labs around the world, where scientists have found evidence suggesting that chemicals designed to prevent fires are getting into your children’s blood and rewiring their brains, leading to attention deficit disorder, hyperactivity, hearing problems, slow mental development and, possibly, cancer. They’re not great for adults either — men with high blood levels of flame retardants had a decreased sperm count, and women took longer to conceive — but because children’s nervous systems are still developing, they are even more vulnerable.

Chemical flame retardants have been on the market since the 1970s, and are used in everything from computers to upholstery, including nursing pillows, cribs, strollers and fleece baby carriers. In the past 10 years, there’s been an explosion of evidence that the most widely used kind, called PBDEs (polybrominated diphenyl ethers), do more harm than good — especially when used in baby products, which have little chance of bursting into flames. The problem is that the chemicals can flake off the products and land in your baby stroller, your couch, your computer desk and your carpet, ending up being inhaled or swallowed by people and pets.

The EPA is so concerned about this risk that last month it proposed putting PBDEs on an official list of Chemicals of Concern, a new, short roster of products that pose an unreasonable hazard to consumers. If the list is approved by the Office of Management and Budget, it won’t quite have the weight of law but will send a message to consumers and manufacturers. But banning these chemicals has proven an intensely difficult task, as the $4.1 billion chemical industry manages a massive lobbying campaign against states that try to ban them, and individual scientists whose work raises questions about their safety.

Last December, the EPA was able to negotiate a voluntary phaseout of one ubiquitous flame retardant, known as “Deca.” Two other types were taken off the market in 2004. But there are more than 200 kinds of PBDEs, and the industry is developing different mixtures to replace the banned chemicals.

“The industry moves a few molecules and calls it a new product,” says Kathleen Curtis, policy director of Clean New York, an environmental advocacy group based in Albany. “Going after these flame retardants one at a time is like playing Whack-a-Mole. You knock one out and another one pops up. They are just buying time.”

Deborah Rice, a highly regarded Maine toxicologist who initially served on an EPA advisory panel on flame retardants, said, “Absolutely, the substitutes will be as bad or worse if they are halogen compounds — bromine or chlorine. The bromine industry is just creating new compounds to replace Deca. It’s a game.”

The latest replacement that regulators may want to whack is a flame retardant based on chlorine instead of bromine. The industry says it’s safe, but these chlorinated chemicals are closely related to a product called Tris, which was banned from children’s pajamas in 1977 because it was absorbed into the skin and was found to cause gene mutations. But Tris is now present in a commercial mixture used in furniture foam, baby strollers and other products. “People continue to be exposed to chlorinated Tris, which we already know is a very potent mutagen and probably a carcinogen,” said Linda Birnbaum, the director of the National Institute for Environmental Health Sciences, in a speech last September. Years ago, Birnbaum, formerly a top flame retardant researcher at EPA, said she did not believe Deca was a health threat, but recent studies changed her mind. She also expressed concern about the prospect of flame retardants interacting with other toxic compounds in the body: mercury from fish; BPA from a water bottle or pesticides in fruit. “Our propensity to think one chemical at a time is probably not where we should be headed,” Birnbaum said.