Women were ordered to move out of a broadcasting centre yesterday after a study confirmed an exceptionally high rate of breast cancer among the female staff.

Employees had long been puzzled by the apparent coincidence of a high number of sufferers among workers at the Australian Broadcasting Corporation’s regional headquarters in Brisbane. Now a scientific panel has concluded that the risk could not be put down to chance, although the cause remained unknown.

Men will continue to work in the building until the end of next month, when the centre will be shut down. Normally 350 people work there.

A dozen women who have worked in the offices have had breast cancer diagnosed over the past decade. At least one has died. Seven worked around the television newsroom, and most had been employed for five years or longer.

The five-month study, led by Professor Bruce Armstrong, of Sydney University, one of Australia’s foremost breast cancer experts, concluded that women at the centre were six times more likely than other women to develop breast cancer.

Yet they did not have a higher level of personal risk factors such as smoking or family histories of cancer, and there was no evidence that the building contained increased risks such as elevated levels of radiation.

Professor Armstrong said: “It’s a very substantial clustering in one part of the operation. It suggested the possibility of specific risk.

“This is an unusual cluster and on that basis it ought to be obvious what the cause is. But it is not obvious.”

Mark Scott, the ABC managing director, said that the results of the study were disturbing for staff.

They will be temporarily rehoused in the offices of their commercial television and radio rivals.

Last night some of the women who developed breast cancer were reported to be preparing to take legal action against the ABC for damages.

Staff first raised concerns almost five years ago.

David Waters, a spokesman for ABC’s Brisbane journalists, said that the company’s handling of the matter, before the Armstrong report, had been tokenistic, sometimes dismissive and overwhelmingly inadequate, and he gave warning that the number of sufferers could rise. “There could be a lag factor for women working here,” he said. “We hope to God that is not the case.”

When the scientific study of the site began in July, several of the women employees who had already had breast cancer diagnosed spoke of their anguish.

Jo Stone, a journalist, said: “It’s devastating to hear and it’s frightening and I am really angry. I want to know why.”

Nadia Farha, also a journalist, said: “You wonder, you know, should I still be working there? Your head says, be sensible, they can’t find anything, but your heart says, maybe there is something there. There was, but no one can say what.”