Three road workers and a garda were injured yesterday afternoon in an explosion at a road construction site in Ballinteer.
They were treated in hospital but their injuries were not thought to be serious.
The explosion happened at Kingston Avenue, where workers were burning off surplus explosives used to blast granite.
Houses in the area were also damaged. A tree trunk landed on the roof of one, damaging tiles and a gutter. Debris landed in the driveway of another. Other houses had windows broken.
Gardai had been on the scene to supervise the explosives for security reasons.
The building contractors Ascon are building the Southern Cross Motorway and have been blasting granite in the area for the past year.
Ms Maura O'Connor said she was in her house on Kingston Grove when the explosion occurred. "It was very loud. I was about to run out to see what happened and I thought `stay where you are' . . . my ears are still ringing from it," she said.
"Thanks be to God all the kids were back at school because some of the debris hit the green where they play." The Minister of State for Labour, Mr Tom Kitt, who heard the explosion from his home in nearby Pine Valley, said it was a miracle no one had been killed. "I saw at first hand the very sizeable stumps of trees which were thrown on to an open space where children would have been playing an hour later," he said.
"If that had hit any youngster, they would have been killed instantly." People were very shocked, he added.
Ascon had a good record in health and safety and had been carrying out explosives in the area for over a year, he said. Health and Safety Authority inspectors had arrived quickly to investigate, the Minister told a residents' meeting last night. "I spoke to the health inspectors on the ground. They were in there very shortly afterwards." He had asked them to give him a full report of the incident as soon as possible, he said.
Mr Brendan Barrett, chief executive of Ascon, said it was investigating the explosion. English subcontractors Amco is involved in blasting at the site.
Mr Barrett said Ascon representatives visited residents yesterday evening to apologise for the explosion and to assess damage.