Geologists and national park officials are warning people not to get too close to the lava entering the ocean because of the danger of a lava delta or bench collapse and explosion.

Lava has been entering the sea since July 26, creating about five acres of new land called a lava delta or a lava bench.

The lava delta is unstable, supported by loose rubble, and could collapse without warning, sending fragments of molten lava and hot rocks to the cliffs above the ocean entry, officials said during a media briefing Tuesday.

In addition, the white plume formed by the interaction of lava and seawater contains hydrochloric acid and tiny particles of volcanic glass, which can irritate the lungs.

Officials urge people hiking to the ocean entry to stay upwind of the plume and far enough away from the cliff to view the scene safely.

There are two ways to hike to the flow — from the end of Chain of Craters Road in the Hawaii Volcanoes National Park and from the county viewing area in Kalapana. Both hikes are long — about 10 to 12 miles round trip and are not for everyone.

Hikers should bring plenty of water and proper footwear and clothing. Bring a flashlight and extra batteries if planning to walk back in the dark.

Hikers are also urged to respect the Hawaiian culture and not to poke the lava with sticks or roast marshmallows or other food on the lava.