6. Flame Retardants, Friend or Foe? Why Federal Government is So Into This?
You probably start to wonder how polyurethane foam can be used at home at all, given its almost explosively nature under fire. Well, that is where a class of chemicals called flame retardant enters our bed. Its purpose is to make solid gasoline burn less rapidly so it can still find a place in our home. The upside of relying on flame retardant to control fire still remains debatable as removing ignition source may play a more constructive role. The downside, however, has become very clear as most common ones turned out to be of long term and persistent adverse health effect. In 2010, nearly 150 scientists signed a statement raising concern about safety of two most common flame retardants[1].
History of Flame Retardant
Large scale flame retardant application in home furnishing started in early 1970s[2]. Federal regulation played a critical role in that process. A few highly publicized burn accidents in 1940s generated a high level of public concern over flammability of fabrics in household. In response, The Flammable Fabrics Act (FFA) of 1953 was passed to regulate the manufacture of highly flammable clothings. The 1953 FFA was fairly lenient and only banned those “explosively flammable”[3]. In 1967, FFA was amended to include interior furnishings as well as paper, plastic, foam and other stuff in apparel and furnishings[4]. The requirement then was fabrics must take longer than 4 seconds to ignite when exposed to open flames. In early 1970s, manufacturers of furniture started to move away from traditional material such as wool and began to adopt polyurethane foam and synthetic fiber based filling. To still meet the more stringent regulatory requirement, adding flame retardant is the method of choice.
Mattress Flame Resistance Standard
In 1973, a separate flammability requirement for mattress was enacted, i.e. so called 16 CFR part 1632. Mattress has to withstand light cigarette on its surface without burning(the exact requirement is char length in any direction is not more than 2 inches)[5]. In 2007, in a move to further strengthen the flammability standard, Consumer Products Safety Commission requires mattress to withstand open flame from gas burner for 30 minutes without itself burning in a meaningful way. This new rule is called 16 CFR part 1633.
8. Why It Is Not Listed on The Law Label?
The law label for mattress now states that “This mattress meets the requirements of 16 CFR Part 1633(federal flammability (open flame) standard for mattress sets) …”. How does the mattress do it? Not a word. That is because no regulation requires the labeling of flame retardants used in mattress, if any. In fact, the exact formula of flame retardant inside each mattress is commercial secret.
Let us take a look at the common flame retardants used in mattress.
9. First, Meet PBDEs, Cousins of PCBs
There are a few ways to slow down a fire. The most effective one is to fight the flame, the core of a fire. One group of flame retardants, halogen organic compounds, do exactly just that. The word halogen derives from Greek, meaning “salt-former”, referring to a group of chemical elements which produce salt in union with a metal. Fluorine, Chlorine, Bromine and Iodine are elements within this group. However, among those four, only chlorine and bromine are effective in the flame fighting role. Chlorine flame retardants are mainly used in plastics because they offer good stability. However, compared to brominated flame retardants, higher quantity is needed to achieve the same flame retardancy. The most common brominated flame retardants are so called PBDEs(Polybrominated diphenyl ethers).
Cousins of PCBs, bad by nature.
PBDEs are cousins of PCBs and have similar chemical structures as well. Please refer to another post on this blog about PCBs[6]. The major difference between them is that chlorine was substituted by bromine in PBDEs. Each PBDEs molecule contains between 1 to 10 bromine atoms and they are named accordingly, using either Greek or Latin number prefix, such as Tetrabromides(4), Pentabromides(5), hexabromides(6), hepta-(7), octa (8 ), nona(9), deca(10)[7]. Different molecules have slightly different properties and are used as flame retardant for specific applications. For example, Penta is used in polyurethane foam; Deca is used in wire insulation, consumer electronics and Octa is used in personal computers and small appliances. They are the three most common commercial formulations[8].
In most application, PBDEs are blended into the plastics or fabrics. The concentration by weight ranges widely. An ordinary polyurethane foam seat cushion sold in North America contains around 30% of PBDEs by weight[9,10,11]. Not surprising at all given the stuff PBDEs have to work on is also called “Solid Gasoline”. PBDEs shares most of the traits of PCBs. It is highly persistent and difficult to destruct, chemcially or otherwise. It is able to accumulate in animal and human bodies and cause neurological development delays in children, disrupt normal thyroid and reproductive functions, especially in male [12].
How did PBDEs become so popular while PCBs got banned?
PCBs has much longer history than PBDEs and its toxicity began to show clearly in many cases by 1970s. The ban on it was decades overdue. However, 1967 FFA demanded an effective flame retardant and PBDEs was the one of choice. It is cheap and effective. In 1976 The Toxic Substances Control Act was enacted and regulates the introduction of new chemicals and made it much harder to introduce something new. But PBDEs were grandfathered in and no question was asked. Given its effectiveness and low cost, as well as the federal flammability demand, PBDEs’ use began to take off.
During the whole process, toxicity and safety of PBDEs were never tested. So you have something today very common yet so similar to PCBs.
How bad it is now? What is the PBDEs level in our body?
Testing shows that the concentration of PBDEs double every two to five years[13]. In 2008, one study found the level of of PBDEs in children average 62 ppb and 25 for their mothers. Another source claims the average concentration level among Americans to be 30~80 ppb[14]. Experiments have shown that adverse neurological effect can be observed on the order of a few hundred ppb level. EPA sets a reference dose to be 7 ppb which is “believed to be without appreciable effect”.
************* Part 2 of 4 *************
To be Continued
No comments yet.