Behind the label focus: PFOS

| 1st July 2007
Firefighting foam laced with this toxic chemical was used to extinguish the Buncefield oil depot inferno, leaving a deadly legacy. Was it necessary?

In February this year, cattle breeder Christopher Archer entered the barn where one of his pedigree British White cows was calving. He found the calf dead; its paralysed hind legs were crumpled underneath its body and an open red sore, clearly visible at the base of its spine (see page 14), showed where the vertebrae of its spine had failed to fuse together.

In other circumstances, Archer, a farmer with more than 23 years’ experience of breeding rare cattle, might not have given this a second thought. But this was his ninth miscarried or stillborn calf in two years. The year before, out of nine pregnant cows, six had miscarried, two had given birth to bull calves with unusually large heads, which died during calving, and one had been born healthy but smaller than expected. His farm’s calving success rate, which was normally between 50 and 70 per cent, had dropped to an inexplicable 11 per cent.

A little over a year previously, in December 2005, a strange dirty-white snowfall had begun to float down onto Archer’s land: the airborne residue of the fire-fighting foam being used to tackle the inferno raging at the Buncefield oil depot in Hertfordshire, two-thirds of a mile away. The foam contained a chemical known as perfluorooctane sulphonate, or PFOS, which works to increase the spread of fire-fighting liquids, making them more effective. Feeding his cattle that day, Archer watched as his cows mistook the foam for food and went to eat it.

Any misgivings he might have had about the foam were allayed over the days and weeks following the fire, when a succession of public bodies – namely the Environment Agency, the Health Protection Agency (HPA), the local authority and the fire service – issued advice saying that the foam was no cause for concern. The only consistent advice in the event of any accidental contact was to wash the affected area.

That any one of these public bodies could have been unaware of the toxic and carcinogenic properties of PFOS is inconceivable. In 2001, under pressure from environmental bodies and mounting evidence that PFOS was accumulating in human bodies and the environment, US chemical giant 3M voluntarily ceased manufacture of PFOS – a highly lucrative compound that was used in everything from greaseproof food packaging to Scotchgard fabric treatment. In 2004, the Environment Agency produced a thorough risk analysis of the chemical. Its researchers concluded: ‘…PFOS should be classified as ‘Toxic’ and carry the Risk Phrase R48 [danger of serious damage to health by prolonged exposure]. There is also support for classification as toxic for reproduction.’

Following this research, which also showed a link between the chemical and bladder cancer in humans, the Government drafted proposals to restrict the sale and use of PFOS in the UK, and to phase out the chemical from fire-fighting foams. Yet at Buncefield – the fuel depot for Heathrow – 50,000 litres of foam containing PFOS were sanctioned for use.


Gold Command

When the kerosene tanks at Buncefield exploded, Hertfordshire Police convened a strategic command team, known as Gold Command. At the table were representatives from the police, the fire service, central Government and the Environment Agency. Confronted by the biggest industrial blaze in peacetime Britain, firefighters on the ground were quick to realise they lacked both an adequate supply of water and stocks of foam, and called for reserves to be trucked in.

It took more than eight hours, however, before Gold Command agreed to the use of foam, which hints at the contentiousness of the decision. One fear, voiced by the Environment Agency, was that the contaminated firewater – the chemical soup comprised of water, foam and fuel chemicals – would enter the water courses and contaminate the water supply to north London. Yet the go-ahead was given, seemingly as a result of political pressure.

Kelvin Hardingham, a firefighter with 30 years’ experience, who was drafted in to provide expert advice, was baffled by the decision. ‘The fire was in the middle of a field and not going anywhere,’ he told trade magazine Industrial Fire World. ‘The buildings around it were already destroyed. There were eight or nine tanks that weren’t on fire that we could protect. Again, I asked, do we really want to put this out?’

Conservative MP for Hemel Hempstead, Mike Penning, who was himself a firefighter for eight years, was equally perplexed by the decision to tackle the blaze and is certain political pressure was being brought to bear.

When the fire erupted, the Government and Fire Brigades Union were in dispute. In urban areas, fire stations were being proposed for closure; while 20 high-volume water pumps (HVP) had been bought as part of a £188m programme known as New Dimension – set up in the aftermath of 9/11 to provide a rapid response in the event of a terrorist attack, and used to justify the controversial restructuring of the brigade. Disputes between the fire brigade and the effects of New Dimension were being addressed by the now defunct Office of the Deputy Prime Minister (ODPM).

Penning says that the ODPM pressured Gold Command to request 15 of the New Dimension pumps to assist with extinguishing the fire, to prove the value of the investment  and associated restructuring programme. This is more than political posturing. Nearly every fire service in the county that put out a news item on the fire referred in full to the use of the HVPs, used the same photograph, and acknowledged the importance of the New Dimension programme. Extinguishing the fire certainly offered the opportunity to present the new flagship anti-terrorism initiative in the best light.

These super-pumps – each of which can supply 8,000 litres of water every minute – require a correspondingly vast supply of foam concentrate. Their introduction to put out the Buncefield fire led to an increasingly frenetic dash for firefighting foam. Supplies came from every available source, no matter how old or what chemicals they contained.

Of the 786,000 litres of foam concentrate supplied to the site, at least 600,000 litres was supplied by fire-services company Angus Fire, and was PFOS-free. Angus Fire’s Technical Specialist, Mike Willson, estimates that of the remainder, most would have been supplied to other fire services by his company, and only 50,000 litres of foam used in the blaze would have come from old stocks containing PFOS.

Had there been more haste and less speed, it would seem that the fire could have been controlled and extinguished PFOS-free.

Danger signs

The actions taken in those smoke-filled December hours might have been justified if everything had gone according to plan and the PFOS-contaminated firewater had remained safely sealed within the confines of Buncefield oil depot. But the sealants connecting the bunds (dams) erected to catch the run-off melted in the heat of the fire.

The PFOS-contaminated firewater gushed through the cracks and formed into a pool 200 metres long and 20 metres wide in nearby Cherry Tree Lane, directly above a borehole that leads to the area’s chalk aquifer – the source of north London’s drinking water.

By May 2006, test boreholes dug by the Environment Agency were showing PFOS contamination of groundwater in the area around Buncefield. Before Buncefield, there was no safe limit set for PFOS contamination levels in UK water. However, in May 2006, the Drinking Water Inspectorate (DWI) set a limit of three micrograms per litre. Yet in 2005, the Environment Secretary Margaret Beckett had drafted legislation that would see anyone importing PFOS into the UK serving a two-year prison sentence. Penning wanted to know why the chemical had suddenly been given a ‘safe limit’ in water: ‘I cannot see the logic that says that, on the one hand, this stuff is so dangerous that it should be a crime to import it into the country at all and, on the other hand, it’s all right for my constituents to drink it, albeit in very limited quantities,’ he told reporters at the time.

Safety confusion

A year on and the advice as to what levels of PFOS contamination are safe has changed again, becoming more complex in the process. In May this year, the limit of PFOS in water above which the supply is considered ‘unwholesome’ had dropped to one microgram – a third of the level identified a year previously. Yet measuring levels of PFOS in water was not made a statutory duty. Rather, water companies are only required to inform the DWI of PFOS contamination if levels rise above nine micrograms per litre. At lower levels of contamination, water boards are expected merely to ‘put in place measures to reduce concentrations below one microgram per litre as soon as is practicable’ and to ‘consult with local health professionals’. In other words, your doctor might know that you have been drinking water laced with PFOS for months, but neither the regulator nor the public would have any idea.

More disturbingly, the DWI guidance observes: ‘...the Inspectorate understands that there is considerable uncertainty in estimates of dietary exposure to PFOS for young children. Uncertainty in these estimates suggests childhood exposure from drinking water may be appropriately restricted to a value in the range zero to 2.5 micrograms per litre.’

Water coming out of a tap is not divided into ‘child’ and ‘adult’ streams. According to these regulations, children could quite easily be consuming levels of PFOS, the effects of which are ‘uncertain’ before eitherthe 3mcg or 9mcg triggers are reached. The local water company, Three Valleys Water, says that the only borehole used for drinking water near to Buncefield had been closed for maintenance work before the explosion and has not been reopened, and a spokeswoman said that the company had ‘no immediate plans to return the source back in to supply.’

But eventually, the borehole will be reopened. A spokesman for the Environment Agency told the Ecologist, ‘I’m sure they’ll want to, just because of their water resources. This year has seen one of the wettest winters on record, but last two years we’ve had a drought, and they [Three Valleys] were under a lot of pressure to reopen the borehole.’

Abstraction poses further risks. The act of drawing water from the borehole can shift the plume of contamination, sucking contaminants down through the aquifer. The question is, will we be any the wiser about safe levels of PFOS when that happens?

Archer asked a simple question: is PFOS safe? The array of answers he has received is alarming. The Environment Agency sent him a CD-ROM containing an Excel spreadsheet depicting the results of their chemical monitoring, and a letter. Unable to use a computer, let alone decipher a chemical analysis, the CD meant nothing to him. The letter told him that the groundwater quality was ‘generally OK’; levels of PFOS were below those set by the DWI for tap water.

The letter went on to assure Archer that ‘the results do suggest that no plume of contamination has moved under the site in the period February 2006 to the present’. The letter is dated 11 May 2007. Less than a month earlier, however, a news release on the Environment Agency’s website clearly stated: ‘The results [from our boreholes] suggest that the groundwater under and up to 2 kms to the North, East and South East of the [Buncefield] site has been contaminated with hydrocarbons and fire fighting foams.’

Archer also sought assurance from the Food Standards Agency (FSA), setting out what had happened, including his cattle’s exposure to the foam and their subsequent reproductive problems. He received a letter from the FSA on 17 May 2007, to reassure him that PFOS ‘is not highly toxic’, and that, as it had been used in winter, his cattle must have had limited exposure to the foam as they would have been inside – which they weren’t, as it was a mild winter and the Environment Agency had indicated to him that it wasn’t necessary.

The FSA continued: ‘With regard to possible contamination of meat, it is unlikely that PFOS would be detectable and exposure to low levels of PFOS over a short period would not be a concern... If you are still concerned, I can suggest where you might have samples of your meat tested but I think you would be incurring an unnecessary expense.’

Regulatory failure

PFOS is known to accumulate in proteins; PFOS is known to have effects through the second generation of offspring, can cross the placenta and is bio-accumulative. PFOS is known to cause foetal defects, including ‘delayed ossification [forming of bones] and skeletal variations’ – symptoms seen in Archer’s calves. The FSA’s own document published last year observes that it may be ‘more appropriate to relate the toxic effects [of PFOS] to a body burden rather than to a daily dose.’ And yet it saw no need to recommend tests or express concern over the fate of Archer’s calves.

Consequently, Christopher Archer has little hope of winning any compensation for the loss to his herd, despite a vet’s report that praises his ‘level of management and stockmanship’ and blames ‘the explosion and subsequent chemical fallout’ as the ‘likely cause’ for the disastrous calving record. Archer is sad but pragmatic about his chances. ‘I can’t prove PFOS did this to my cows,’ he sighs, ‘but in 23 years of farming I’ve never seen anything else like it.’

The fire service exists to put out fires, pretty much by any means possible. The FSA, DWI, Environment Agency, HPA, our local authority and government departments are public bodies and have a statutory duty to protect the public. Yet it would seem other concerns took precedence that night.

Buncefield depot is the heart of Heathrow, keeping the planes in the air. In the aftermath of 9/11 it is feasible that the government wanted to show the world it was prepared. According to some experts we made a potentially deadly mistake in defeating a dying fire. Now we have contaminated ground water in an aquifer from which the drinking water for three million customers is drawn.

Are the levels of PFOS in the water safe? Maybe your GP knows, because the agencies established to protect our interests are clearly at sixes and sevens.

How PFOS slipped through the safety net

PFOS was first manufactured in 1948 by the 3M Company. It is now a ubiquitous environmental pollutant.

For more than 40 years it was used in a wide variety of products. Firefighting foam was perhaps the single biggest use of PFOS. But its water- and oil-repellent properties meant that the chemical found its way into a plethora of commonly-used products: for example, coatings for candy wrappers, fast-food boxes and bags for microwave popcorn. It was also used in waxes, polishes and cleaning products, window treatments, carpets and furnishing fabrics, mattresses and shower curtains. It was used as a stain and water repellent for clothing, footwear and accessories and on upholstery in private cars, planes and trains. It was utilised in the metal plating industry, in photographic products, in mould release agents, paints and varnishes.

Logic would have dictated that such a widely used chemical would find its way into the ecosystem and into animals and humans. But traditional testing methods for persistent  pollutants missed it entirely because, unlike the majority of industrial chemicals, PFOS doesn’t accumulate in fat, it binds to proteins.

This unique characteristic meant that it was 40 years before researchers found PFOS in supposedly clean samples from blood banks all over the world. It was subsequently found in polar bears in the Arctic, dolphins in Florida, seals and otters in California, albatross in the mid-Pacific. By 2000 3M had voluntarily withdrawn PFOS from the marketplace – all the while maintaining that this was purely a precautionary measure and that there were no known health hazards from exposure. Subsequent data has proven them wrong.

In mammals in the wild, chronic PFOS exposure has led to disturbances of the hormone and immune systems, and vitamin A levels, as well as reduced bone mineral density. It is also a reproductive toxin. Long before Buncefield, the US Environmental Protection Agency observed: ‘PFOS accumulates to a high degree in humans and animals. It has an estimated half-life [the time it takes to clear half the ingested PFOS from the body] of four years in humans. It thus appears to combine persistence, bioaccumulation, and toxicity properties to an extraordinary degree.’

This article first appeared in the Ecologist August 2007


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