An investigation is underway after two separate fires in Sarnia early Monday.

Shortly after 2:30 a.m. police and fire crews responded to the 400 block of Kathleen Street for a structure fire.

Three units sustained signficant damage and police say neighbouring units were evacuated, but there were no injuries.

“Just, fire everywhere,” says Cheryl Heath, a neighbour who lives across the street. “I woke up to my family yelling and screaming, I came running outside and saw that the unit was on fire so I tried helping by letting everyone come into my house to let get them out of the smoke."

Then just before 4:30 a.m. a second fire in the 600 block of Rayburne Avenue destroyed a residence and caused significant damage to neighbouring properties.

“The second fire came in on Rayburne Avenue, so two (fire) crews had to head that way including one overtime crew, so we had two simultaneous structure fires...I wouldn’t say it’s that common especially this close in time and distance,” says Officer Mike Otis, Sarnia Fire safety educator.

Police believe that residence was unoccupied, and are not reporting any injuries at this time.

People are being asked to avoid both areas as police and fire investigators as well as the Ontario Fire Marshal's Office look into the cause of the fires.