There has been widespread outrage and anger in Mayo following the vandalism of a defibrillator unit at the summit of Croagh Patrick.
Gardaí in Westport are investigating the incident which occurred over the weekend.
A large rock was used to break open the door of the emergency unit and the defibrillator was taken out and the pads were removed.
It is now badly water damaged but none of the equipment was taken.
Founder of Eco Powered Cabinets Darren Forde, who produced and installed three units on the mountain in 2022, said: "It's really sickening that a piece of life-saving equipment would be damaged in this way. These vandals broke all 24 hinges to remove the door, which was left unlocked.
"We didn't think this unit would require CCTV or having to lock it. It will be an awful shame if we had to lock these units which are life-saving and designed to give people immediate access."
It is the second time one of the solar-powered boxes has been damaged in Mayo.
Mr Forde's company have installed several defibrillator units around the county and one in Béal an Mhuirthead was vandalised in recent weeks.
"That was shocking enough but we thought it was a once-off. But to cause this damage to a vital piece of equipment on the very top of Croagh Patrick is heartbreaking.
"These units have got through the very worst of all weathers in wind, rain and snow. Now the water damage has destroyed the electrics and it is no longer in use.
"The sheer scale of getting this unit to the summit of the mountain was a very costly and physically arduous exercise. We will certainly try to replace it and have one up and running in time for Reek Sunday but it is a hugely challenging task."
There have been a number of fatal cardiac arrests on the mountain in the past decade and the defibrillator units have been key in saving the lives of several pilgrims and climbers since they were installed.
One person was successfully resuscitated in November and is recovering well at home.
The public has been advised that the defibrillators at the cone and the foot of Croagh Patrick are fully operational and available for use.
Anyone with information relating to the incident is urged to contact Westport Garda Station on 098 50230.
