Debating the environmental costs and safety gains of use of flame retardants

January 16, 2013 at 2:40 pm | Posted in Feature Articles | 1 Comment
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The flame retardant (FR) industry developed rapidly in the 1960s and 70s as a response to the rapid uptake of flammable synthetic foams and plastics in furnishings and electronics, and the ensuing increase in number and severity of domestic fires. FRs are now a lucrative business, with a 1.9 million-tonne annual production creating 5.1 billion dollars of turnover.

A move now under way to overhaul sections of California’s fire safety regulations (Technical Bulletin 117) for upholstered furniture will, if it goes through in current form, greatly reduce the need for FRs in residential furnishings across the US. Conversely, in the EU, there is a lobbying campaign under way to implement a Europe-wide ignition standard modelled on that used by the UK which would likely increase FR use.

Changes in regulations with implications for FR use are of strong financial interest to the FR industry, while environmental health concerns about FRs suggest there may be substantial gains to be made from limiting their use. The debate has evolved to become highly polarised between the industry and environmental lobbies, as one side is accused of promoting false information about fire safety and promoting chemophobia, and the other of downplaying the harmfulness of FRs and exaggerating their efficacy in preventing fire deaths.

The environmental health issues

Many of the halogenated FRs are persistent and bioaccumulative. After four decades of use, they are ubiquitous throughout the built and natural environment. Human exposure is primarily through diet and house dust in the home, with toddlers particularly highly exposed because of their low body weight and their hand-to-mouth behaviours.

There is a strong correlation between regulatory standards and FR exposure: California has the highest exposure in the world, the UK the highest in Europe, while in mainland Europe where ignition requirements are limited or even absent, exposure is much lower. Elevated levels of PBDEs have been found in human blood serum in Californian children at 5 times the US average, and 10-100 times the European and Mexican averages (Frederiksen et al. 2009).

Polybromodiphenyl ethers (PBDEs) are the FRs best-studied for health effects, with animal and epidemiological studies linking elevated levels to infertility, attention disorders in children, impaired neurodevelopment, lower IQ and other effects.

These concerns have led to voluntary halting of use of pentabromodiphenyl ether in the US and its ban in Europe. Polybromobiphenyls (PBBs) have been banned in both the US and Europe. Deca-BDE (often in the literature known by its congener number, BDE-209) is now on the EU REACH list of Substances of Very High Concern, primarily because of concern about the toxicity of its environmental breakdown products and metabolites.

New FRs also present concerns, less because of evidence of harm but because of a lack of any data about harm at all: a recent European Food Safety CONTAM panel report on novel (meaning confirmed presence in consumer goods but not detected in people or environmental samples) and emerging (meaning chemicals identified in the environment, wildlife or people) brominated FRs found 27 compounds in use, but insufficient data to carry out any kind of risk characterisation at all.

An EU-commissioned report looking at all FRs in consumer products identified 42 in current use (Arcadis EBRC 2011). For 32 relevant to consumer exposure, toxicological data was available for 16 substances. Due to lack of data on production volume, not one single compound could be subjected to environmental risk assessment.

US research suggests that, as PBDEs are phased out, they are becoming replaced by tris(2,3-dibromopropyl) phosphate (TDBPP, banned in children’s sleepwear), Firemaster 550 and chlorinated organophosphate flame retardants (Dodson et al. 2012). 94% of new US furniture contains flame retardants, nearly all next-generation compounds with little known about their potential health effects  (Stapleton et al. 2012).

The efficacy debate

The Californian fire safety regulation TB117 spells out two tests which each component of a piece of furniture must pass if it is to go on sale. One looks at how quickly the material burns when ignited by a smouldering cigarette, and the other by a small open flame.

The smoulder test was instituted because cigarettes are the leading cause of furniture fires. In 2009, 27% of residential fires were caused by cigarettes igniting furniture. The same is true in Europe, with cooking fires in second place (Kobes & Groewegen, 2009 [PDF]). Most fatal fires happen at night, starting in the living room, so effective fire detection and damping is essential for giving people enough time to be warned of a fire and to escape.

FRs are used because modern furniture stuffing is highly flammable. There is not, however, a readily-apparent consensus view on whether or not adding FRs to furnishings is an effective measure for preventing fire deaths.

A report commissioned by the FR industry (Emsley et al. 2005 [PDF]) attributed approximately 50% of the reduction in residential fire deaths since 1988 to improvements in the effectiveness of smoke alarms and the extent of their installation, and the other 50% to the use of FRs in furnishings.

There are reasons for doubting the veracity of these numbers, with changes in smoking habits, reduced use of exposed heating sources, stricter building regulations, and general improvements in standard of living all potential contributors to an overall reduction in fire death incidence in this time, none of which are controlled for in the Emsley report (Hull & Stec, 2012).

A report (Arcadis EBRC 2011) presenting data from beyond the UK suggests little association between flammability requirements and fire deaths; for example, France has much less stringent ignition standards than the UK but a lower incidence of domestic fire deaths. Any comparisons between countries are made more uncertain by lack of authoritative data, with no European standard for reporting of fires.

There is little correlation between ignition standards and fire deaths. Source: Arcadis EBRC 2012.

Comparing fire deaths before and after changes in regulation in a single country, as in the Emsley report, may therefore give a better picture of the usefulness of FRs; however, the major cultural changes which can take place over the 20+ year data period may not be much less significant than regional differences at a given time. Overall, neither the domestic nor international comparison seems especially solid.

The water can be further muddied by public relations campaigns pushing bad papers into mainstream discussion (Roe 2012). Overplaying a generalisation from 8 fires in a suburb of Stockholm to extrapolate electrical appliance fire deaths in the rest of Europe (somewhat unfairly covered by Roe & Callahan 2012, given the paper was presenting a model forced into making very broad assumptions in the face of a chronic lack of data, see McNamee 2012) has been exposed as another lobbyist’s trick.

Escaping the impasse

There is nothing new about controversy around chemicals used for fire safety: halons, asbestos, PCBs, and Tris flame retardants in children’s pyjamas are all compounds with fire safety benefits outweighed by environmental and health concerns.

Leaving FRs to one side, the fundamental question is whether or not the ignition standard makes furniture any safer, contributing to fewer injuries and deaths in fires? Again, the data seems equivocal, with no major change in fatalities in the US from fires started by open flames, when a reduction should be expected throughout the 1980s as more furniture across the US was manufactured in compliance with California’s TB117. (See chart.)

Death from fires caused by small open flames has not reduced during the time period that FR use in furniture has increased, suggesting either FRs or the standard or both are ineffective measures in preventing these deaths. Source: Babrauskas et al. 2012

Fire scientist Dr Vyto Babrauskas is one person sceptical about the open-flame standard (Babrauskas et al. 2012), arguing that in real furniture fires the outer fabric ignites first, and once the fabric is burning, the foam is presented with a flame challenge many times larger than the original small flame, and will ignite whether or not flame retardants are present.

Whether or not this matters is disputed by other fire scientists, who argue that nonetheless the fire burns cooler, or releases less carbon monoxide, or it gives a longer period of time before a room hits the temperature at which everything within it ignites.

The correctness and relative significance of each these factors in terms of overall contribution to preventing fire deaths is still the subject of lively debate; as an observer, it is very difficult to know whom to believe.

For a good sense of the complexity of the debate, a high-quality exchange is in the comments to this C&EN article, with all principle players in the article weighing in to a heated discussion: 

If the ignition standard is ineffective, then we have an environmental and health cost with no fire-safety benefit, so there is a strong argument for ditching the standard.

But then, what should we replace it with? Is simply deleting the open-flame ignition requirement a sufficient revision? This may not be thinking broadly enough, as the data only shows that open flame standards make no contribution to reduced fire fatalities, not that the right standard could not make a more significant contribution to reducing fire fatalities, possibly without the environmental impact encouraged by the current standard.

This would take the debate beyond a polarised discussion of whether or not we need flame retardants, or whether or not the standard works, to a discussion of what we want the standard to achieve, and how to formulate it to achieve that.

A standard could incorporate limits on the toxicity of permissible compounds and ensure they have an adequate pedigree of environmental safety; it could be set high enough that we could be sure that the gains outweigh the environmental costs; finally, it could be based on more realistic fire scenarios to produce much less equivocal evidence of benefit than the simplistic smoulder and naked flame tests currently do, giving a more certain and measurable result and a solid evidence base for decision making in fire prevention strategy.

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  1. […] Since this is a unhelpfully polarised discussion, we thought it would be worth trying to get to the bottom of the issues. We present what we discovered in this month’s edition of Health & Environment, which you can read here. […]

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