HOMES in Dalgety Bay, Fife, have been contaminated by military radioactive waste in breach of safety limits, putting the health of residents at risk. A new survey for the Ministry of Defence (MoD), seen by the Sunday Herald, reveals that the gardens of up to nine houses could be polluted with high levels of radium-226 from old warplanes.

The MoD is now coming under growing pressure to dig out the contamination, for which it has previously denied responsibility. It is also being asked by the Scottish government's green watchdog to clean up the foreshore at Dalgety Bay, which is suspected of being even more polluted.

Dalgety Bay was the site of Donibristle airfield, where many aircraft were dismantled at the end of the second world war. The dials in the planes were coated with luminous, radioactive radium so that they could be read at night.

Dials were removed and incinerated, along with other waste. Afterwards the remaining ash and clinker were tipped on the land and used to help reclaim some of the coastline.

Radioactive contamination in the area was accidentally discovered in 1990 by a monitoring team from Rosyth naval dockyard. Since then intermittent surveys have been carried out, leading to the removal of 23 drums of radioactive waste to Rosyth.

Last year a firm of consultants commissioned by the MoD's Defence Estates carried out the most detailed and intrusive investigation so far of the extent of the contamination inland. Their final report was posted last week on the website of the government's Scottish Environment Protection Agency (Sepa).

High levels of radium-226, beaming out 21 becquerels of radioactivity per gram, were discovered in "ashy materials" in the gardens of two private homes. Four other properties in the same street, The Wynd, are suspected of having similar contamination, as well as possibly three other homes on Sealstrand and The Spinneys.

All these houses cover an area where the radium dials were thought to have been salvaged and burnt. If the contamination is as widespread as experts believe, residents could be exposed to radiation above the Health Protection Criterion (HPC) for radioactively contaminated land agreed by the Scottish and UK governments.

"The results of the preliminary risk assessment indicate that residents of properties located on the former salvage section footprint may be exposed to doses in excess of the HPC," the report concludes.

Studies have shown that exposure to small doses of radiation over many years carries an increased risk of cancer. Owners of properties contaminated with radioactivity from the Sellafield nuclear plant in Cumbria have had difficulty selling them.

The MoD report recommends detailed further investigations to assess the exact nature of the risk. This would enable the MoD to make "informed decisions regarding potential future liabilities regarding the presence of potential contamination in these gardens," it says.

According to the report, lower levels of contamination were detected at other sites in Dalgety Bay, including the sailing club, the coastal footpath and a nearby woodland. The survey did not cover the foreshore, where a 2005 Sepa survey found nearly 100 radiation hotspots.

Sepa welcomed the new report from the MoD, which was recently presented to a forum involving local people. The MoD was understood to be carrying out further work in the housing estate, which Sepa expected to consider soon.

But Sepa's Allan Reid added: "However, Sepa remains concerned that the MoD has not yet committed to extend this work to the more significant contamination on the foreshore and would encourage it to undertake work in this area as soon as possible."

The MoD was also urged to shoulder responsibility for the contamination by Green MSP Patrick Harvie. "The MoD left this toxic legacy lurking under people's gardens and they must take responsibility for a full clean-up operation," he said.

In response to questions, the MoD issued a very brief statement. "The MoD is currently working closely with Sepa to investigate any contamination issues associated with the former Donibristle airfield," it said.