Scientists Are Playing Whack-a-Mole with Toxic Flame Retardants

In the 1970s, manufacturers started adding chemical flame retardants to everyday household products. Couches, chairs, beds, pillows, electronic devices like microwaves, hair dryers, televisions, and children’s products like cribs and changing pads — all were treated with a class of chemicals called polybrominated diphenyl ethers, or PBDEs, to meet flammability and safety standards.

But decades of research have revealed these chemicals as anything but safe. Exposure to PBDEs can lead to birth defects and neurodevelopmental disorders in children, for example. Plus, these chemicals take time to break down and have been classified as persistent organic pollutants. That means they are released into the air from treated items and can spread long distances by air and water, eventually contaminating ecosystems far from their origin, like polar and alpine landscapes. As a result, beginning in 2004, PBDEs were largely phased out and/or banned in the US and Europe, and many manufacturers have turned to an alternative class of flame retardant: organophosphate ester flame retardants, or OPFRs.

The question is: Are these substitute chemicals any safer?

In a report published yesterday in Environmental Science & Technology Letters, a team of chemists and toxicologists answer that question with a resounding no. OPFRs, it turns out, are just as toxic and polluting — if not more so — than the PBDEs they’re meant to replace.

“This is what I like to call the whack-a-mole game in chemistry,” says Marta Venier, a chemist at Indiana University and co-author of the report. “You whack one chemical down and another pops up that’s fairly similar in structure and characteristics. You haven’t solved the problem. You’ve just created a different one.”

Arlene Blum, executive director of the Green Science Policy Institute and co-author of the study, has seen this whack-a-mole phenomenon before. In 1977, Blum published a report labeling a common flame retardant in children’s pajamas called tris as a carcinogen. That chemical was subsequently banned in pajamas, only to be replaced by another version of tris with the same mutagenic properties. “The story is always the same,” says Blum. “After years of research and advocacy, a harmful chemical is phased out, and its replacement is usually a similar chemical about which we know very little.”

In 2008, having established herself as both a chemist and a celebrated mountaineer (Blum led the first American and all-female expedition to the top of Annapurna I in Nepal in 1978), Blum founded the Green Science Policy Institute to more effectively communicate the science of harmful chemicals, particularly the “six classes” of chemicals found in common products. Her goal, she says, is for manufacturers and policymakers to “see the writing on the wall” that most flame retardants and other similarly hazardous substances cause more harm than good and therefore should be phased out of production completely.

By that time, years of research and advocacy had already identified PBDEs as toxic, and, starting in 2004, policymakers in both the United States and Europe had begun phasing the flame retardant out of use. Many researchers still see the end of PBDE use as a win for human and environmental health. One study suggests that regulatory phase-outs have worked quickly to reduce the environmental strain of PBDEs, despite how widespread and persistent these chemicals were at the height of their use.

But in the meantime, the use of organophosphate flame retardants continues to increase, along with the risks they pose.

Compared to PBDEs, relatively little is known about OPFRs. The new report, a roundup of the current literature on OPFRs, suggests that obtaining the scientific evidence to regulate this substitute flame retardant could take years. That being said, the compiled data from toxicity tests, risk assessments, and epidemiological studies paint a picture of OPFRs that looks concerningly similar to PBDEs. For one, both chemicals have been associated with developmental disorders and lower IQ in children, as well as infertility and cancers in adults.

And, like PBDEs, organophosphate flame retardants can travel far from their origin. As journalist Marla Cone describes in her book Silent Snow: The Slow Poisoning of the Arctic, this persistence quality has environmental injustice implications. Wind and ocean currents bring many persistent organic pollutants to the marine food web of polar regions, where Indigenous communities suffer higher levels of exposure to chemicals they don’t even use.

Though OBFRs have not been officially classified as persistent organic pollutants, research has shown that they also spread long distances. In fact, organophosphates have been shown to be even more water soluble than PCBEs. In the new report, the researchers point to multiple measurements that show that OBFRs have already reached significantly higher levels in remote polar regions than PCBEs did at peak use.

“Not only have we not eliminated the problem,” says Venier. “We’ve created a bigger one.”

The answer, according to the report, is for manufacturers to bypass flame retardants altogether, without waiting for policy to catch up with the science. For example, the researchers suggest using inherently flame resistant materials in product design, like barriers or less flammable fabrics, rather than depending on chemical solutions. Manufacturers could also redesign products, like one TV manufacturer that used an external power source to minimize the need for flame retardants in the plastic case around the TV.

“We ought to be able to come up with more innovative solutions than filling our homes and our products with toxic or potentially toxic flame retardants,” says Blum. “Manufacturers need to go beyond these chemicals and come up with safer products.”