Housebuilders Cruden originally intended to remove hundreds of lorryloads of waste from the land at Tarbert Drive, Murieston, which was used to dump ash from Edinburgh's incinerated rubbish at the start of last century.
Then it emerged some of the contaminated material would be buried under gardens and driveways with owners of the 18 new homes planned for the site warned not to build extensions onto their houses.
Now an email has come to light from environmental advisers IKM Consulting, on behalf of Cruden, setting out an "alternative approach" which would involve keeping all the contaminated material on site.
Top soil would be removed, the ash then piled at one side of the site while areas were then excavated for it to be buried.
The email claimed this would reduce the exposure of the waste material and also reduce vehicle movements from the site.
But residents say even if it meant there would not be fleets of lorries carrying the toxic waste past their homes, they are worried about all the ash being dug up, moved around the site and then left there..
Mother-of-two Gillian de Felici said: "The land is fine as long as it's left alone but once you disturb it that's when you start to release the contaminants into the atmosphere.
"It was bad enough the soil was going to be disturbed and taken away but to have it still there is a huge concern.
“They are going to bank it up at the side of the development that backs onto my cul-de-sac. We know some of the things that are in the soil, including cancer-causing agents, and it's going to be backing onto gardens with kids there. Every time it rains is the run-off going to come down off the soil and into the gardens? Is it going to blow into the gardens when it's windy?”
And she said removal of the toxic material was the key reason the development was set to get the go-ahead despite previous similar applications being rejected. “Surely if they’re not going to do that any more the whole issue of planning permission needs to be looked at again.”
The Scottish Government planning reporter, announcing he was minded to approve the development, said: "Contamination on the site from the historic disposal of incinerator ash poses risks to human health, and so the site is shut off to public access. This convinces me that the site is currently unsafe and that remediation would be a prerequisite of any development."
However, despite the IKM email, Cruden insisted it did not plan to keep all the waste on site. A spokesman said: “The proposed method of remediating the site remains as detailed in the proposed remediation strategy. This strategy has already been approved by the council’s contaminated land officer and its consultants. Cruden Homes do not intend to depart from the principle of the remediation strategy which involves a retention of material onsite and offsite disposal.”