REHOBOTH BEACH — An early Friday morning fire has been ruled accidental by the Delaware fire marshal. The fire, which occurred around 3 a.m., badly damaged a building on Olive Avenue in Rehoboth Beach.

The fire originated inside the third floor unit when an electrical malfunction occurred in ceiling lights, the fire marshal said. No one was home inside the third floor unit, but the building’s fire alarm system did notify the occupants in unit one. The other dwelling was not occupied.

Damage was estimated at $150,000. There were no reported injuries.

The Rehoboth Beach Volunteer Fire Company initially responded to the fire.