Big Island fire investigators are trying to determine the origin of several brush fires that kept firefighters busy in Hilo and Waikoloa several on Thursday.

Four brush fires broke out all around 3:30 p.m. along Daniel K. Inouye Highway, or Saddle Road, between the 48- to 50-mile markers and between the 15- to 17-mile markers on Highway 190 . Approximately 330 acres of pasture and open fields were scorched.

Road closures remain in effect for public safety. Highway 190 is closed from the 14-mile marker at the junction of Daniel K. Inouye Highway (New Saddle Road) on the Waimea side to the 17-mile marker on the Kona side. Also, Daniel K. Inouye Highway is closed from the junction with Highway 190 to the junction with the Old Saddle Road near Pohakuloa. Traffic from both closures is being detoured to Old Saddle Road.

The blaze was fought by 78 Big Island, military, forestry and volunteer firefighters.

Earlier in the day Hilo firefighters were called at 12:32 p.m. to extinguish a brush fire on Hoaka Road that burned one acre. The brush fire at a residential lot was brought under control at 12:55 p.m. No structures were damaged. No injuries were reported.