THE country's long hot summer has been blamed for the religious anomaly which left parishioners with burns and blisters from holy ash.
People who received ash on their foreheads to mark the start of the Lenten period were left in shock after the holy mark started to burn.
But Galway priest Fr Malachy Hallinan solved the mystery after sending off a sample of the ashes to the Public Analysts Laboratory.
Tests discovered that the leaves used to prepare the mixture were too dry, and as a result the ash turned caustic when mixed with water.
"It's really due to the very dry year we experienced," Fr Malachy said.
"What we usually do is store whatever leaves are left over from Palm Sunday.
"I myself keep the leaves in my garage, but there is usually twice as much dampness around in other years.
"This year the weather was so dry that the leaves were left bone dry and the ash was like powder."
Dr Andrew Flanagan of the the Galway Public Analyst Laboratory, who studied a sample of the ashes, urged the priest to highlight the problem.
"He told me there had been a previous case of this happening here in the Galway area, but it had not been publicised, and he also asked me to get it out to make other priests aware," Fr Malachy said.