Navy investigators have unable to determine the cause of Oahu’s largest wildfire this year that swept through Waianae and Lualualei valleys charring nearly 1,200 acres.

 The wildfire fire began June 4 at Radford Street and Kolekole Road on Naval Magazine Lualualei and had consumed nearly 1,200 acres. It spread into the areas of the Waianae Kai Forest Reserve.

After interviewing numerous witnesses and examining all the evidence, Navy investigators said the cause of the fire is undetermined, the Navy said today.