Brominated flame retardants are organobromine compounds that have an
inhibitory effect on combustion chemistry and tend to reduce the
flammability of products containing them. Of all the commercialized chemical
flame retardants, the brominated variety are widely used. They are effective in
plastics and textile applications, e.g. electronics, clothes and furniture.
Types of compounds Many different BFRs are produced
synthetically with widely varying chemical properties. There are several
groups: Polybrominated diphenyl ethers: DecaBDE,
OctaBDE, PentaBDE Polybrominated biphenyl, not
manufactured anymore Brominated cyclohydrocarbons
Other brominated flame retardants with different properties and mechanisms
Decabromodiphenyl ether - In August 2012, the UK authorities proposed
decabromodiphenyl ether as a candidate for Authorisation under the EU‘s
regulatory regime on chemicals, REACH. On 5 July 2013 ECHA withdrew Deca-BDE
from its list of priority substances for Authorisation under REACH, therefore
closing the public consultation. On 1 August 2014, ECHA submitted a
restriction proposal for Deca-BDE. The agency is proposing a restriction on the
manufacture, use and placing on the market of the substance and of mixtures
and articles containing it. On 17 September 2014, ECHA submitted the
restriction report which initiates a six months public consultation. A decision
could be adopted by mid-2016. Hexabromocyclododecane is a ring
consisting of twelve carbon atoms with six bromine atoms tied to the ring. The
commercially used HBCD is in fact a mixture of different isomers. HBCD is
toxic to water-living organisms. The UNEP Stockholm Convention has listed
HBCD for elimination, but allowing a temporary exemption for the use in
polystyrene insulation foams in buildings.
Tetrabromobisphenol A is regarded as toxic to water environment. This flame
retardant is mainly used in printed circuit boards, as a reactive. Since
TBBPA is chemically bound to the resin of the printed circuit board, it is less
easily released than the loosely applied mixtures in foams such that an EU risk
assessment concluded in 2005 that TBBPA poses no risk to human health in that
application. TBBPA is also used as an additive in acrylonitrile butadiene
styrene. Contents in plastics
Content of brominated flame retardants in different polymers:
Production 390,000 tons of brominated flame
retardants were sold in 2011. This represents 19.7% of the flame retardants
market. Types of applications
The electronics industry accounts for the greatest consumption of BFRs. In
computers, BFRs are used in four main applications: in printed circuit boards,
in components such as connectors, in plastic covers, and in cables. BFRs are
also used in a multitude of products, including, but not exclusively, plastic
covers of television sets, carpets, pillows, paints, upholstery, and
domestic kitchen appliances. Testing for BFR in plastics
Until recently testing for BFR has been cumbersome. Cycle time, cost and level
of expertise required for the test engineer has precluded the
implementation of any screening of plastic components in a manufacturing or
in a product qualification/validation environment.
Recently, with the introduction of a new analytical instrument IA-Mass, screening
of plastic material alongside a manufacturing line became possible. A
five-minute detection cycle and a 20-minute quantification cycle is
available to test and to qualify plastic parts as they reach the assembly line.
IA-Mass identifies the presence of bromine, but cannot characterize all the
BFRs present in the plastic matrix. In February 2009, the Institute for
Reference Materials and Measurements released two certified reference
materials to help analytical laboratories better detect two classes
of flame retardants, namely polybrominated diphenyl ethers and
polybrominated biphenyls. The two reference materials were custom made to
contain all relevant PBDEs and PBBs at levels close to the legal limit set out
in the RoHS Directive of 1 g/kg for the sum of PBBs and PBDEs.
Environmental and safety issues Many brominated chemicals are under
increasing criticism in their use in household furnishings and where children
would come into contact with them. Some believe PBDEs could have harmful effects
on humans and animals. Increasing concern has prompted some European
countries to ban some of them, following the precautionary principle more common
in Europe. Some PBDEs are lipophilic and bioaccumulative. PBDEs have been found
in people all over the world. Some brominated flame retardants were
identified as persistent, bioaccumulative, and toxic to both
humans and the environment and were suspected of causing neurobehavioral
effects and endocrine disruption. One particular target group is Firefighters
who are exposed to brominated fire retardants during firefighting
operations and is resulting in cancer rates that far exceed the general
public. As an example, in Europe, brominated flame retardants have gone
through REACH and when risks were identified appropriate risk management
options were put in place; such was the case for commercial Penta-BDE and
commercial Octa-BDE. Given the current state of waste disposal in the world,
there is a potential for BFRs to be released into the environment.
See also Tris(2,3-dibromopropyl) phosphate
References Further reading
Kyle D'Silva, Alwyn Fernandes and Martin Rose. "Brominated Organic
Micropollutants—Igniting the Flame Retardant Issue". Critical Reviews in
Environmental Science and Technology 34: 141–207. doi:10.1080/10643380490430672.
Law, Robin J.; Kohler, Martin; Heeb, Norbert V.; Gerecke, Andreas C.; Schmid,
Peter; Voorspoels, Stefan; Covaci, Adrian; Becher, Georg; Janak, Karel.
"Hexabromocyclododecane Challenges Scientists and Regulators".
Environmental Science & Technology 39: 281A. doi:10.1021/es053302f.
Cynthia A. de Wit. "An overview of brominated flame retardants in the
environment". Chemosphere 46: 583–624. doi:10.1016/S0045-6535(01)00225-9. PMID
11999784. Young Ran Kim; et al.. "Health
consequences of exposure to brominated flame retardants: A systematic review".
Chemosphere 106: 1–19. doi:10.1016/j.chemosphere.2013.12.064.
External links MPI Milebrome - Brominated Flame
Retardants Bromine Science and Environmental Forum
European Brominated Flame Retardant Industry Panel
SFT: Current State of Knowledge and Monitoring requirements: Emerging "new"
Brominated flame retardants in flame retarded products and the environment