The lorry driver, who was in his 50s and a foreign national, died at the scene on the main street of Emyvale village in Co Monaghan.
The milk tanker completely demolished a cottage by the N2 motorway, but the owner was in Scotland on holiday.
The vehicle then careered into an adjoining house, ripping out the front wall, but a 13-year-old boy who was sleeping upstairs escaped with his life.
Miraculously, the teenager’s mother was out of the house – hanging up the washing on the clothes line in the back garden.
Another house was also damaged by the tanker.
Two local Fás workers also cheated death by minutes as they were working on a footpath near the houses, but took an early tea break.
Fire officers who arrived at the scene initially believed there were people trapped in the rubble of the houses and used thermal imaging cameras to assess the scene. Co Monaghan’s senior assistant chief fire officer Dermot Brannigan said: “That was one of our initial concerns about people in the houses.
“The structure of the houses was precarious and very dangerous. It was miraculous nobody else was injured.” Up to 50 emergency personnel attended, including gardaí, fire officers and Civil Defence members.
Gardaí were investigating whether the driver had fallen asleep or suddenly fallen ill at the wheel.
Local Fine Gael councillor Pat McKenna, who visited the scene of devastation, said it was a blessing nobody was injured or killed apart from the driver.
“There was terrible destruction.
“When I got there I saw the emergency services cutting the driver out of his cab and taking him away in an ambulance.”
The deputy mayor of Monaghan County Council added: “One house was completely demolished, but luckily the owner was in Scotland on holidays today.
“A young lad was asleep in an upstairs bedroom at the back of another two-storey house. If he had been at the front of the house, it could have been a different story.”
Milk which spilled over a wide area had to be contained by officials from Monaghan County Council. Mr McKenna added: “Two Fás workers were working on the footpath a few minutes before. But it started to rain and they took an early tea break.
“A shrub they had been planting was ripped up by the lorry. Anybody walkingthe street could have been involved.”
The scene of the accident is on a bend close to the Silver Hill duck farm nearthe village. Engineers later moved in to examine the houses and assess theirrisk to public safety.
The driver was pronounced dead at the scene and his body taken to Navan General Hospital.
Garda forensic collision investigators were at the scene and the road will be closed for a technical examination for most of the day. Motorists were asked to avoid Emyvale if travelling to Derry or to Dublin.
Locals have been campaigning for several years for a bypass around the villageto reduce traffic congestion.
“What has to happen before something is done?” Mr McKenna asked.
“The Emyvale to Monaghan Road is also an accident blackspot. There have been five people killed near Corracrin.
“I am pleading with the authorities to do something now.”
Separately, in neighbouring Co Cavan, a 78-year-old man was killed when the car he was driving hit a lorry near Belturbet at 3.45pm yesterday.