A neurotoxic flame retardant resists environmental breakdown and builds up in the food chain, a new study conducted by researchers from the Boston University School of Public Health and published in the journal Environmental Health Perspectives has found.

“They are persistent in the environment. They don’t get broken down,” lead researcher Alicia Fraser said. “Therefore, it takes a really long time for the contamination to leave our environment and our bodies. Even though we don’t know the health effects at this point, most people would want policies that would stop us from being exposed to them.”

The chemicals, known as polybrominated diphenyl ethers (PBDEs), are closely related to polychlorinated biphenyls (PCBs), which were banned in the 1970s after evidence emerged that they produced birth defects and neurological damage. Flame-retardant PBDEs were introduced at roughly the same time and soon became popular in a wide variety of household and consumer products.

Since the 1990s, evidence has increasingly emerged linking PBDEs to neurological damage in animals. Furthermore, study after study has shown that the chemicals can build up in the human body, particularly in breast milk. Every human population on Earth currently carries PBDEs in their bodies.

In the new study, researchers tested 2,000 people for PBDEs, finding that meat eaters had body burdens 25 percent higher than vegetarians. This provided still more evidence that the chemicals build up in animal fat, resisting degradation.