A COOLING tower at a Hereford cider-making giant has again tested positive for the bug that causes Legionnaire's disease - heightening speculation it is the source of the outbreak that has killed a pensioner.

The latest test results come five days after initial samples taken at the site proved to be "presumptive positive".

Andrew Tector, Herefordshire's head of environmental health, said the tower at the cider-making plant - which produces Woodpecker and Strongbow - has been continuously contaminated, despite previous efforts to disinfect it.

Officials say they cannot be certain HP Bulmer Ltd is the source of the Hereford outbreak - which has now infected 23 people after another case was diagnosed yesterday - but many factors point to that conclusion.

Careful mapping of the movements of people diagnosed with the disease show a pattern consistent with the source being in an area which includes Bulmers' Plough Lane site, he said.

The latest Legionnaire's victim, a man in his 70s, is described as being in a "stable" condition.

The tower has been shut down since last Wednesday and is being rigorously cleansed under the supervision of health and safety experts.

Willie Crawshay, Bulmers' general manager, said the company was treating the situation with the greatest urgency and was co-operating fully with the local task force to eradicate any residual contamination.

"The safety of our employees and the public is of paramount importance and the evaporation plant will remain closed until it has been fully cleaned and tested," he said.

He said the rest of the plant remained fully operational.

"It must be stressed that all Bulmers' products are totally safe for cider drinkers to enjoy," he added.

Dr Mike Deakin, Herefordshire's director of public health, said there could be more cases of the disease diagnosed up until the end of this month.

"We now have to work on the basis that new cases could appear during the incubation period of two to 14 days, starting from last Wednesday," he said.

GPs and hospital staff are on heightened alert to the possibility of the disease and are testing more patients, he added.