By Terray Sylvester

PAHOA, Hawaii (Reuters) – Hawaii authorities scrambled to move tens of thousands of gallons of highly flammable chemicals from the path of lava on Thursday, and the state’s governor warned mass evacuations might be needed as the Kilauea volcano’s eruption became more violent.

After a new fissure opened on Wednesday about half a mile from a geothermal power plant, Hawaii Governor David Ige set up an emergency task force to remove the pentane used in the plant’s turbines. He cited estimates that if the fluid ignites, the resulting explosion could create a blast radius of up to one mile. (1.6 km)

The Puna Geothermal Venture plant sits at the edge of the Leilani Estates residential area on Hawaii’s Big Island where lava from 15 volcanic fissures has so far destroyed 36 structures, most of them homes, and forced the evacuation of around 2,000 residents.

“As more fissures open and toxic gas exposure increases, the potential of a larger scale evacuation increases,” Ige said in a tweet on Wednesday evening.

“A mass evacuation of the lower Puna District would be beyond current county and state capabilities, and would quickly overwhelm our collective resources,” Ige tweeted, saying in a separate post that he signed a request for federal disaster assistance.

The lower part of the Puna District, of which Leilani Gardens is a part, covers dozens of square miles and is home to many thousands of residents. It has the highest possible hazard risks for lava flows, according to the U.S. Geological Survey.

Exposure to very high levels of the sulfur dioxide gas emitted from the fissures can be life-threatening, experts say.

Geologists warned on Wednesday that Kilauea may be entering a more violent phase of explosive eruptions, the likes of which Hawaii has not seen in nearly a century.

Steam-driven explosive eruptions could hurl “ballistic blocks” weighing several tons upwards of half a mile and dust towns as far away as Hilo, some 25 miles (40 km) distant, with volcanic ash and smog.

Hawaii Volcanoes National Park, where Kilauea is located, said on Wednesday it would close most of the park on Friday due to the threat of a possible explosive eruption.

Magma is draining out of the volcano’s sinking lava pool and flowing underground tens of miles eastward before bursting to the surface on Kilauea’s eastern flank in the lower Puna area.

“There’s still quite a fair bit of magma under the ground that’s available to erupt,” Tina Neal, the scientist in charge of the USGS Hawaiian Volcano Observatory, said in a conference call, adding that she saw no end to activity in the east rift zone.

Kilauea has been in a state of nearly constant eruption for 35 years. It predominantly oozes out lava from fissures that flows into the ocean but occasionally experiences more explosive eruptions, such as an event in 1924.

(Reporting by Terray Sylvester, writing and additional reporting by Andrew Hay in New Mexico; Editing by David Gregorio)