Maui fire investigators have not been able to determine the cause of a brush fire that so far has scorched 30 acres in West Maui’s Ukumehame subdivision.

However, investigators believe that it started near a group of homeless encampments discovered in the brush. One encampment was overrun by the flames and was destroyed, but two other makeshift shelters were saved by fire crews. No homes in the subdivision were threatened and no injuries were reported.

At around 10 p.m. Wednesday, the fire was estimated to be 60 percent contained. A heavily wooded area of large trees near the highway was making it difficult to get complete containment. Crews were seeing repeated flare-ups in this area. A Lahaina crew maintained fire watch overnight.

Twenty-six firefighters from Lahaina, Napili, Wailuku, Kahului and Wailea responded to the brush fire that broke out at 12:18 p.m.Wednesday. It has blackened around 30 acres of dry grass and brush in an Ukumehame subdivision.

Maui fire officials said a resident reported hearing a loud explosion just before flames were seen erupting from an open field just north of Pohaku Aeko Street and mauka of Honoapiilani Highway. Winds quickly spread the fire makai towards Honoapiilani Highway, which forced a brief shutdown of all vehicle traffic for about 30 minutes.

While two helicopters made water drops, heavy equipment from the County’s Public Works Department and West Maui Land Co. cut firebreaks around the perimeter in attempts to contain the fire. West Maui Land Co. also assisted with two water tankers at the scene.