Investigators have ruled as arson a late Sunday night fire that left a Cambridge home in ruins. The Maryland State Fire Marshal's Office said it happened shortly after 11 p.m. at te vacant two story dwelling located at 5382 Aireys Road. It took 30 firefighters from the Cambridge Rescue Fire Company approximately an hour to get the blaze under control. The fire caused an estimated $20,000 in damage to the structure and another $1,000 in damage to its contents. There were no reported injuries. Investigators determined the fire started inside the home and was intentionally set by some type of incendiary. Anyone with information about this incident is asked to contact the Lower Eastern Region Office of the State Fire Marshal.