NEW SHOREHAM, R.I. (WPRI) — A report released Friday by the state fire marshal’s office offered new details on the fire that destroyed a historic Block Island hotel last month.

The Harborside Inn is in the process of being demolished after it was deemed a total loss due to heavy damage from the fire that started the night of Aug. 18.

Investigators believe the fire started in the kitchen of the Harbor Grill on the second level. While the exact cause of the fire is still unclear, the fire marshal’s report identified some factors that allowed the flames to quickly spread, namely a buildup of grease in the cooking area.

The report says the fire originated in the area of the kitchen hood, then vented out an exhaust fan and spread upward into the wall cavity.

There was a “large accumulation of grease” on the hood, as well as “throughout the length of the cook line and on every appliance,” according to the report. It also appeared that grease vapors may have been escaping into the wall cavity, which would have accelerated the fire.

“It further does not appear that routine cleaning is conducted on the cooking surfaces,” the report said.

The restaurant manager reportedly told an investigator from the fire marshal’s office that the kitchen hood is cleaned at the start and close of every season (May and September). However, the last hood cleaning was dated May 2022, the report says, which is “outside the allowable time per Rhode Island Fire Code.”

Investigators found the ignition source for the fire was “probably conductive heat from a burner or an ember,” which the report says was caused either by “unattended cooking or failure to maintain protective baffles in the hood.”

The manager said he made sure everything in the kitchen was turned off before he locked up around 10:30 p.m., according to the report, but it’s unknown if someone entered the kitchen between then and when the fire alarm went off at 11:23 p.m.

“The interior camera system was collected but had suffered salt water damage,” the report said. “At the time of this report, the DVR is being analyzed for possible extraction. Without this footage, it is unknown if additional cooking occurred later in the evening.”

The report says a retired firefighter who was staying in the hotel was the first person in the kitchen after the alarm sounded and he tried to put out the flames using an extinguisher. Since he reportedly turned several of knobs in an attempt to shut off the burners, investigators are unsure if any had been left on earlier.

Additionally, the report found the fire suppression system in the kitchen failed to activate.

“The suppression system nozzles did not appear to have released product and many retained their protective caps,” the report said.

An inspection of the property with a K-9 officer revealed no presence of ignitable liquids.

The demolition of the Harborside Inn is expected to be complete by the end of September.