The Department of Health (DoH) has moved to head off a potential public health scare after official research found that babies born near "landfill" waste sites are at risk of birth defects.
The research, published today, has caused alarm because it shows that 80% of the population lives within 2km of a current or closed landfill site where there is a slightly higher risk of birth defects.
Government public health experts, who yesterday called a press conference in an attempt to pre-empt fears raised by the study, said the findings were not clear-cut and contained "uncertainties".
Deputy chief medical officer Dr Pat Troop said: "We cannot say that there is no risk associated with landfill sites, but given the small number of congenital anomalies and the uncertainties in the findings, we are not changing our advice to pregnant women."
She added: "This is very complex research, which is not easy to interpret." The research was "never intended to provide all the answers", she said, stressing that the risk was less than the damage caused by smoking or alcohol to unborn babies.
The research, which was carried out between 1982 and 1997 on eight million pregnancies, is published in the British Medical Journal today. It found a 1% increase in the risk of birth defects to babies born near a landfill site - which increases to 7% for those near a hazardous waste site.
Cases of babies born with low birth weights are 5% higher near landfill sites. Researchers stressed that there was no link to increases in cancer, particularly childhood leukaemia.
The DoH said that, despite the size of the survey, there were a number of technical reasons why it might not be accurate, which is why further research will take place.
The report's authors said: "We know of no casual mechanism that might explain our findings, and there is considerable uncertainty as to the extent of any possible exposure to chemicals found in landfills.
"Further understanding of the potential toxicity of landfill emissions and possible exposure pathways is needed in order to help interpret the ... findings."
Dr Troop said that of the 660,000 babies born each year, up to 12,000 overall would have congenital defects, and that by comparison, today's figures on possible landfill hazards represented a risk to approximately 100 babies.
Ann Hemming, head of landfill waste policy strategy at the Department for the Environment, Food and Rural Affairs, said the issue emphasised the need to look at other ways of disposing of waste.
She said: "There is no risk-free or wholly risk-free form of waste disposal. We would encourage people to look at how they can reduce waste by recycling or re-using goods, or by buying items with less packaging."
A spokesman for the DoH said: "Of the 12,000 babies born with congenital abnormalities each year, overall about 100 are associated with people who live close to landfill sites. Of those, around 60 are associated with living near a hazardous site."
Friends of the Earth accused the government of "safemongering" to avert a health scare over landfill sites. Chief executive Kevin Dunion, added: "The key to solving our waste disposal problems begins with not producing so much waste in the first place."
Labour backbencher Barry Sheerman accused the Treasury of encouraging the use of landfill for waste disposal by failing to impose sufficient tax on the practice.
The tax on dumping waste in landfill sites was increased from £11 to £12 a tonne in the last budget in a bid to make it less attractive. But Mr Sheerman - chairman of Urban Mines, a non-profit organisation that seeks alternative ways of dealing with waste - said this was not enough.
He told BBC Radio 4's World at One: "The villain of the piece is the Treasury, which has been told for a long time that the landfill tax is far too low to divert people from putting stuff into holes in the ground and towards other measures. I think it has got to be a £5 to £10 increase until we get up to the European equivalent level."
