The Manville fire department initially responded to the call of a gas explosion with injuries.
When they arrived they found two PSE&G employees who were injured.
They had been called to work on that boiler before it blew up.
Building officials are trying to figure out if the house is structurally sound.
The staircase leading to the basement was completely destroyed.
Both employees sustained severe steam burns.
One of the workers was thrown several feet because of the blast.
Both workers were airlifted to local hospitals for treatment.
The home owner was also injured in the explosion.
The 88-year-old homeowner was transported to Somerset Medical Center where he was treated for his injuries and released.
The two PSE&G workers, a 54-year-old of Collingswood, N.J. and a 32-year-old of West Deptford, N.J. were injured and taken to area trauma centers.
Fire officials say the utility workers were responding to the boiler because pressure has been building in it.
Detectives from the Manville Police Department, the Somerset County Prosecutor's Office and specialists from PSE&G investigated the cause of the explosion.
The investigation revealed that a boiler located in the basement of the home overheated and exploded.
The cause of the explosion was found to be non-suspicious in nature.
Detectives believe a malfunction in the boiler was responsible for the explosion and the investigation is ongoing to determine the exact cause.