PART of the north’s flagship hospital had to be evacuated after its new £3million heating system blew up.
The blast started a blaze in the biomass boiler room at Raigmore in Inverness and damaged a stairwell and ceiling.
Three people who were working inside at the time escaped unhurt, although one worker will undergo tests today amid fears his hearing was damaged by shockwaves from the explosion.
Members of staff in nearby areas of the hospital were moved to other parts of the complex as a precaution.
They included people working at Centre for Health Science and Ward 11, which was empty of patients in preparation for work starting yesterday on a new children’s ward.
Three fire crews went to the hospital and two firefighters wearing breathing apparatus searched the smoke-filled boiler room.
A brigade spokesman said the top of the boiler was damaged, but the fire had burned itself out before crews arrived.
An increase in pressure in one of the hospital’s two biomass boilers is though to have caused the blast.
The boilers, which burn wood pellets, were installed at the end of 2013 -to save NHS Highland fuel costs – and have been operating since April last year.
Both boilers were switched off as engineers carried out a thorough examination of the machinery.
NHS Highland said the boiler – which is in a standalone building at the rear of the Raigmore complex – would not have to be replaced and the hospital would use its old oil-fired system as back-up until it is repaired.
Highlands and Islands MSP Mary Scanlon said last night: “This is very worrying, given that so many hundreds of people are on site at the hospital at any one time.
“I think that patient and staff safety is paramount and I hope that checks will be done to bring assurances that the working environment is safe.”
An NHS Highland spokesman said yesterday: “Following an internal investigation by the NHS Highland estates department, it has been discovered that the incident at Raigmore Hospital this morning was caused by a build up of pressure.
“There was a release of energy in an economiser from boiler two, which caused this build up of pressure and resulted in a loud bang.
“As a precautionary measure, the three NHS Highland staff members who were in the boiler room at the time have been referred to occupational health.
“One staff member has been given an ENT (ear, nose and throat) appointment to check their hearing has not been affected by the loud bang. There were no injuries as a result of this incident.
“The hospital is now running as normal and no services have been affected.
“The pressure in the economiser has been isolated and there has been no excess damage to the biomass boiler.”
He added that a full investigation into the cause of the blast would be carried out.
The wood pellet boilers, which were installed by Danish firm Weiss, provide up to 80% of the Inverness hospital’s heating and hot water and work with existing boilers.
The two boilers and furnaces each weighs 55 tonnes and is almost 23ft tall.