Legionella has been found in water supplying parts of a cancer treatment ward at a hospital in Edinburgh.
The bacteria was found in the supply of the radiotherapy unit at the Western General Hospital.
NHS Lothian says the source has been isolated and there have been no cases of infection in patients or staff.
The type of bacteria poses no risk of infection to people.
The health board said that as a precaution, a thorough programme of disinfection and cleaning is being carried out, with services moved to other parts of the building.
Two specialist machines have also been closed while remedial works continue.
The remaining radiotherapy machines will be run for extended hours to ensure patient appointments continue to be allocated and carried out as quickly as possible.
Alison MacDonald, nurse director at NHS Lothian, said: “Legionella bacteria was detected during routine water sampling as part of our building monitoring and hygiene vigilance measures.
“The risk to patients and staff is low but we’ve enhanced infection and control measures across the building as a precaution.
“We assure patients that radiotherapy treatments will continue to be carried out as quickly as possible and apologise to anyone who has been affected or had their appointment rescheduled.”
NHS Lothian said the situation is being closely monitored and continuously assessed.