Hexabromocyclododecane, commonly known as HBCD, is a flame retardant that is starting to give a lot of green builders headaches.
Many people have never heard of this chemical compound, used in polystyrene insulation, but it could be in your house. Indeed, you are likely to be carrying some in your body.
This flame retardant has been found in human breast milk, body fat and blood. In the United States, "everyone has it in their tissues. In Europe, where HBCD is more widely used, the exposure is higher," said biochemist Arlene Blum, executive director of the Green Science Policy Institute and an expert on brominated and chlorinated flame retardants.
Not only is HBCD found in human tissues, but it's also found in wildlife and aquatic organisms all over the globe. In the United States, HBCD is carried through rivers and streams to the coasts, where it comes to rest in ocean sediments and enters the food chain. The highest levels of HBCD recorded to date were found in sea lions that were feeding on clams, shrimp and other bivalves off California, Blum said.
The Environmental Protection Agency and the European Chemicals Agency have said HBCD persists in the environment and does not break down into safer chemicals. It is toxic to aquatic invertebrates. According to EPA's HBCD Action Plan, released in 2010, "It also presents potential human health concerns based on animal test results indicating potential reproductive, developmental and neurological effects."
The European Union announced in February that HBCD is one of six substances of "very high concern" that "will be banned within the next three to five years unless an authorization has been granted to individual companies for their use." These substances "cannot be placed on the market or used unless authorization has been granted for a specific use."
How has HBCD become so widespread? Environmentalists have said the most likely primary source is emissions that escape during its manufacture or after it is applied as a flame retardant. Because HBCD is not chemically bound to the material it protects, it will eventually escape into the air, said Alex Madonik, a chemist with the Green Science Policy Institute.
But, Madonik said, in 2008, when the European Chemicals Agency determined that HBCD was a "substance of very high concern," it also concluded that when HBCD is used in insulation, its predicted exposure is low. For this reason, European polystyrene insulation manufacturers might request authorization to continue using HBCD. But even if this is granted, Madonik said, "they will be strongly encouraged to develop alternatives."
What is EPA's position on HBCD? Despite efforts to get precise information from its Office of Pollution Prevention and Toxics, I did not get answers. But EPA's Action Plan states that it is "considering initiating rulemaking" that "could take the form of a comprehensive ban" or "a more targeted regulation to address specific activities." EPA "intends to publish a notice of proposed rulemaking by the end of 2011," it said.
All this raises an obvious question for American homeowners and green home-builders: Is it okay to use materials containing substances that raise havoc with the environment and increase the chemical burden in everyone?
There are no easy answers.
Polystyrene insulation is favored by green-home builders because it creates an extremely energy-efficient building envelope. Reducing home energy use is a cornerstone of green building because it helps to cut greenhouse gas emissions. Home energy use accounts for about 20 percent of the greenhouse gases emitted by the United States every year.
