Radiation from experiments carried out by a prizewinning nuclear scientist more than 100 years ago may be responsible for four cancer deaths at a university.
Three academics and a computer assistant have died after working in the same building.
The one-time laboratory at Manchester University was used by Ernest Rutherford at the turn of the last century.
He is known to have begun a series of experiments using radioactive material in 1906.
Officials from the Health and Safety Executive have now ordered a review to determine whether former lecturers, students and ancillary staff were contaminated by traces of radon and polonium left in the building.
All four of those whose deaths are under review worked in the university's psychology department, which moved into the old physics department in 1972.
Dr Arthur Reader, 69, died from pancreatic cancer last week. Shortly before his death his wife, Grace, said his illness appeared to be "more than a coincidence."
In February this year Vanessa Santos-Leitao, 25, a computer assistant who worked in the building from 2006, died of a brain tumour.
Dr Hugh Wagner, a psychologist, died last year of pancreatic cancer. He was 62 and had spent two decades working in room 2.62 of the Rutherford Building.
It was in this room in 1908 that Rutherford, assisted by a colleague, Thomas Royds, carried out experiments using radon.
The Rutherford Building is also known to have contained quantities of polonium, the substance which killed Alexander Litvinenko, the Russian dissident, in November 2006.
One of Dr Wagner's colleagues, Dr John Clark, worked in the room directly below 2.62. He died of a brain tumour in 1992 after taking early retirement.
Concern about the Rutherford Building first emerged in June when three of the university's psychologists published the findings of a private investigation in June.
Although they were unable to establish any direct evidence to link the deaths of their colleagues to radioactive contamination, university officials have confirmed that the Rutherford Building was the subject of a precautionary decontamination exercise in 1999.
The Manchester coroner, Nigel Meadows, has requested that a post mortem examination should be carried out on Dr Reader's body. He hopes this will determine "whether or not his death was unnatural - that is, whether or not he was exposed to anything during the course of his employment that may have caused or contributed to the cancer."
Dr Wagner's widow, Rachel, said recently: "Many dear friends and colleagues - and there are many others whom I don't know - have worked in the building over the years: they could be alarmed by the report and will be wanting accurate information.
"I am reassured that the university is looking into not only the building's history, but also its occupancy."
A university spokesman said: "We believe the evidence presented to date does not support a connection between the deaths of former staff and possible exposure to radioactive contamination. It is important to stress that we do not believe there to be any risk to current occupants of the Rutherford Building.
"It was surveyed by an independent specialist company as part of the refurbishment in 2006 and some minor contamination - below levels reportable to the Health and Safety Executive - were found in a limited number of locations.
"This was removed by specialist contractors and the building was re-surveyed prior to the move into the building of its current occupants."
The Health and Safety Executive has confirmed that current radiation levels in the building are safe.