National Park Service and Hawaii County fire crews continued Friday to battle a wildfire that broke out on 3 acres of dry ohia woodland and scattered koa trees.

The fire, which started Thursday afternoon, forced park officials to close Mauna Loa Road from Highway 11 and temporarily evacuate Namakanipaio Campground.

The fire was about a quarter-mile west of Kipukapuaulu. As of 8 a.m. Friday, the blaze was 50 percent contained.

No structures or homes were threatened. Park officials said the cause is under investigation but that it was not intentionally set.

Meanwhile, dry conditions and the accompanying risk of fire have prompted some road closures in Hawai‘i Volcanoes National Park.

Park officials have closed Hilina Pali Road from the Mauna Iki Trailhead and Mauna Loa Road at the gate past Kipukapuaulu. Daytime hiking and bicycling will be permitted, and backcountry camping on Mauna Loa is allowed with a permit.

Campfires are prohibited at Namakanipaio Campground and Kipukapuaulu until further notice. The use of fuel stoves is allowed.

Also, access to Ainahou Ranch will be restricted to essential personnel and authorized vehicles only, the National Park Service said by email Friday.

“We’ve had an extremely hot and dry summer in the park, and across the island which escalates the risk of fire,” Hawai‘i Volcanoes National Park Chief Ranger John Broward said in a statement. “Hot components on motor vehicles have historically contributed to the increased risk of fire, and by reducing the number of vehicles, we can mitigate the potential for a catastrophic event.”

Honokowai Beach water tainted

The state Clean Water Branch has issued a warning that the water off Honokowai Beach has tested positive for potentially harmful microorganisms.

Routine monitoring found that the levels of enterococci bacterial were at 137 units per milliliter, above the threshhold of 130 units, for the beach north of Kaanapali.

The branch, part of the state Health Department, said bacteria, viruses, protozoa or parasites in the water could make swimming risky.

“Children, the elderly, and people with weakened immune systems are the most likely populations to develop illnesses or infections after coming into contact with polluted water, usually while swimming,” the branch said by email Friday.