An inquiry has declared it unlikely that chemicals found in soil caused two toddlers to develop a very rare cancer.
Sharon Pymer died of a very rare form of acute myeloid leukaemia
Traces of toxins were found in Leftwich near Northwich, Cheshire, where 19-month-old Rebecca Watts and Sharon Pymer, 18 months, were neighbours.
They died in 2005 from a form of acute myeloid leukaemia - which affects about three children a year in the UK.
But scientists from the Health Protection Agency (HPA) found there was no evidence of a health risk.
The verdict came at the end of a two-and-a-half year long investigation.
However, the agency has recommended the families of the toddlers are rehoused on compassionate grounds.
Rebecca Watts and Sharon Pymer both died of acute megakaryoblastic leukaemia.
Their parents, who live back-to-back, claim the illness was caused by benzene, a toxin which has been found to be present on land in the area.
The estate was built on a former landfill site and the HPA said it was possible that is were the chemicals originated.
Cancer charity Cancerbackup said the causes of acute megakaryoblastic leukaemia are mostly unknown but high level exposure to radiation may increase risk, as can some toxic chemicals.
The HPA said the parents should be rehoused
However, Dr Alex Stewart, Consultant in Health Protection with HPA North West, said there was no evidence that chemical contaminants had caused the girls' illnesses.
"This was a very rare form of leukaemia and to find it in two children living in such close proximity, effectively on the same plot of land, merited extensive investigation," he said.
"In partnership with Vale Royal council, we met with the residents and involved them fully in the process.
"We have found that there are no significant health risks to children or adults and no evidence chemical contaminants discovered would have caused the leukaemias."
He added: "Nor is there any evidence that the health of other residents on the estate has been adversely affected by the small amount of substances found in the ground.
Rupert Adams, head of environmental health and housing services with Vale Royal Borough Council, said: "I hope that the residents will now feel reassured their homes and gardens are safe."
The HPA is continuing to investigate the case is now writing to the girls' families to ask for permission to examine medical records to search for a link.