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Toxic Gas Hypothesis

Response from FSID to final report of the government appointed Expert Group to Investigate Cot Death Theories: Toxic Gas Hypothesis   

FSID welcomes the report of the Expert Group chaired by Lady Limerick. After an exhaustive investigation of the toxic gas hypothesis lasting three and a half years, methodically examining every aspect of the claim both by reviewing existing research, as well as by commissioning new research, the Expert Group has concluded that there is no evidence to support the claim that fire retardants in PVC cot mattresses cause cot death.

Joyce Epstein, Secretary-General of the FSID, said:

"The toxic gas theory has now received the most thorough possible attention, and has been rejected as unfounded. It brings to a close a ghastly episode in public health scare-mongering prompted by The Cook Report in 1994, which broadcast its programme without responsibly substantiating the evidence.

"Thousands of parents were distressed and misled by the story, convinced that mattresses kill babies. Even now a survey shows that more parents think mattresses cause cot death than are aware, for example, that smoking in pregnancy is dangerous for babies.

"10 babies still die every week in this country from cot death. We know some of the risk factors, but we need serious research - not the TV kind - to find out the causes and prevention of cot death."

Over all conclusions of report

The overall conclusion was that there was no evidence to substantiate the toxic gas hypothesis that antimony- and phosphorus-containing compounds used as fire retardants in PVC and other cot mattress materials are a cause of SIDS. Neither was there any evidence to believe that these chemicals could pose any other health risk to infants.

Background to investigation

In 1989 Mr Barry Richardson said he had done research that showed antimony in mattresses released toxic gas which, he said, caused cot death. In 1990 the UK Department of Health and the FSID commissioned studies to investigate the toxic gas claim but neither found any evidence to support it. In 1994 the television programme, The Cook Report, broadcast unpublished research that said cot death babies had higher antimony levels in their blood and liver than babies who died of other causes, and asserted that the antimony came from cot mattresses.

Main research findings

Research commissioned by the Expert Group and others (including the FSID) found:

bulletThere is no difference in antimony in cot death babies and other babies
bulletAntimony is found in most babies, even before birth, ie before they could have had any exposure to mattresses. It could come from maternal diet, but antimony is everywhere, including common household dust
bulletThere is no correlation between antimony concentration in mattresses and that in babies
bulletYet another attempt to replicate Mr Richardson's original experiment failed, even though Mr Richardson co-operated with it fully and agreed that the same methodology had been followed; in other words, in normal cot-like conditions it is not possible to generate toxic gas from antimony in mattresses
bulletNo antimony was added to mattresses before 1988, and yet cot deaths were occurring pre-1988 at the rate of about 2,000 per year (now about 500 per year)
bulletThe year after antimony was first added to mattresses, 1989, was the year that cot deaths began to decrease - at first a small decrease and then, after 1991 following campaigns to sleep babies on the back, a rapid decrease; cot deaths dropped in all by over 70% between 1988 and 1995.
bulletMr Richardson's claim that the decrease was due to publicising his advice to wrap mattresses is unfounded: as of 1993-95, only 2% of babies were sleeping on wrapped mattresses; babies have also been found to die on wrapped mattresses
bulletCot death occurs in countries where no antimony has been added to mattresses
bulletWhen comparing babies who die and babies who live, proportionately more of the babies who live sleep on PVC mattresses
bulletAccording to Mr Richardson's theory, death occurs because the toxic gas reduces acetylcholinesterase, leading to heart failure, but post mortem examinations of babies who die show no reduction in acetylcholinesterase
bulletThe fungus, Scopulariopsis brevicaulis, that Mr Richardson said was present on all cot mattresses and which was essential for the release of toxic gases, is actually hardly ever present on cot mattresses

The original artcile can be seen at

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