FREMONT, Calif. – Researchers from the Cancer Prevention Institute of California (CPIC) have detected an increase in the levels of two flame retardant additives called Polybrominated Diphenyl Ethers (PBDEs) in the blood of California women collected over a four-year period, beginning approximately five years after these compounds were banned in California in 2006.

PBDEs were mainly used to treat polyurethane foam cushioning in furniture and carpet padding. It has been suggested that PBDEs may cause cancer and other adverse health effects.

This suggests that the banning of the PBDEs may not be enough to protect people from exposure.

“While earlier research indicated that the banning of these chemicals was successful at reducing human exposures, the results from our study suggest that we should be careful not to declare victory too soon,” says Susan Hurley, leader of the CPIC study.

As one of the largest studies on this topic to date, the analysis included 1,253 women between the ages of 40-94 who were participating in the California Teachers Study, an-ongoing statewide study of female professional public school employees initiated in 1995 primarily to study breast cancer. Participants in the current study were restricted to those without breast cancer.

The results of this study stand in contrast to earlier studies that indicated some initial declines in body burden levels shortly after the compounds were banned. Earlier studies, however, primarily focused on much younger women. Thus, it is possible that the lack of declines in the current study reflect differences in how older women metabolize and eliminate these chemicals from their bodies. An alternative explanation is that the way people are being exposed may have recently shifted.

As the first study to show increases in PBDEs in blood since the U.S. ban, the authors note the value of biomonitoring in better understanding how people are currently being exposed. “If replicated by other studies, our findings underscore the need to evaluate additional regulatory efforts to safely manage the disposal of PBDE-laden products to mitigate human exposures” adds Susan Hurley.

“Like PCBs, DDTs and other chemicals that do not break down easily, we will have PBDEs in our bodies for decades” said Myrto Petreas, one of the co-authors of the study. According to Meredith Williams (not involved in the study) “PBDEs are classic examples of chemicals that were used before we had a full understanding of the harm they could cause. Our Safer Consumer Products Program intends to promote safer chemicals as substitutes for hazardous ingredients in consumer products.”