An expert witness against residential cellular towers admitted during cross examination in Supreme Court yesterday that there is "no proof'' exposure to radio frequency radiation causes cancer.

Dr. David Carpenter was giving evidence as cellular phone company, Bermuda Digital Communications (BDC), seeks to hold onto their lease with West End Properties Ltd.

The subsidiary of the Fairmont Southampton Princess Hotel has issued notice to BDC terminating their lease out of concern that the tower poses a health hazard to hotel employees who reside on the grounds.

Dr. Carpenter, a public health specialist, is a leading proponent of the health dangers exposure to radio frequency radiation may cause. Last year he addressed members of the Warwick citizens group, Community Against Radiation Emissions (CARE) -- formed by residents to stop the tower's developement.

But under cross examination by BDC lawyer Narinder Hargun, Dr. Carpenter admitted no research conducted to date has proved that exposure to radio frequency radiation (low ionising radiation) causes cancer.

Dr. Carpenter however also insisted no research has disproved that exposure to such radiation is unhealthy and he noted that while the radiation might not be the cause, it may trigger cancer cell development.

"We have not proven causation,'' he said. "But there is reason for people close to cellular towers to have concern.'' Pointing out that he is not in favour of more regulation, Dr. Carpenter said the public simply needs to be more informed.

"I don't know that we should wait until the evidence is so firm that it is a health hazard before we act,'' he said.

"My position is not radical or extreme. I believe we should be careful as these issues are unresolved. I'd say if something is going to reduce the likelihood of cancer, then let's do it.'' Asked if his opinion is out of the norm in scientific circles, Dr. Carpenter said it was not: "I hope I'm at the front of the pack,'' he said, "but not way out in front.'' Dr. Carpenter was not able to offer statistically significant research which showed exposure to radio frequency radiation is a health concern and he agreed that non exposure is neither possible nor necessary.

"I am not opposed to cellular communications at all,'' he said, "but the balance between risk and benefit must be looked at and you cannot say conclusively from the research done, that there is no risk.'' Given Bermuda's population density, cell towers will inevitably be near to residents and Dr. Carpenter suggested towers be erected on "rocky atolls just off the coast''.

The case being heard by Assistant Justice Philip Storr is expected to conclude today with closing arguments from Mr. Hargun for BDC and lawyer Jai Pachai for West End Properties.