Officials are trying to determine what caused a house fire in Mount Vernon.Fire officials say the blaze broke out around 5 a.m. at the home of South First Avenue. According to officials, the fire moved up the side of the house and spread to the roof.Officials say about 21 firefighters were needed to get the blaze under control. Two firefighters suffered injuries while battling the fire.It is the second time this year that there has been a fire at the home. In February, the home was damaged in an electrical fire that cost thousands of dollars to repair. The family says it will need to find a new place to live temporarily, but is thankful that everyone made it out safely.