KAILUA, KONA, Hawai'i — Fire crews yesterday continued to keep an eye on two Big Island brushfires that scorched nearly 30,000 acres this week.

The largest fire started north of Waikoloa Village shortly after 2 p.m. Monday and prompted the overnight evacuation of part of the subdivision on Tuesday.

The 25,000-acre blaze that came within yards of some Waikoloa homes no longer posed a threat to the community, said Lanny Nakano, acting Hawai'i County Civil Defense Agency administrator.

Five firefighters were assigned to monitor the perimeter overnight and to knock down any flare-ups, Nakano said.

The state Department of Health had advised village residents with chronic respiratory conditions to take precautions as strong winds continued to blow dust and ash in the area.

The cause of one of the Big Island's largest wildfires on record has not been determined.

The second blaze, sparked Tuesday night by a vehicle fire, spread along both sides of Akoni Pule Highway northwest of Kawaihae.

Ten county firefighters and 12 state Forestry and Wildlife Division personnel were to maintain fire breaks overnight and monitor hot spots.

Meanwhile, County Councilman Peter Hoffmann, whose district includes Waikoloa, said the community's Fire Wise program paid off.

Hoffmann started the program three years ago, scheduling regular work days to cut and clear brush around the village.

Last month's focus was on the west side of the village, the same area that burned this week.

"We had 22 people out that day and hauled away six trucks of green waste," Hoffmann said. "The fire stopped right at that line."