Two lava flows reached the southeast coast on Sunday
Authorities in Hawaii have warned people to stay away from dangerous "laze" fumes as molten lava from the Kilauea volcano reaches the Pacific Ocean.
Two lava flows reached the ocean along the southeast Puna coast on Sunday, the US Geological Survey (USGS) confirmed, but a crack underneath one of the channels diverted the molten rock into "underground voids".
When hot lava hits the ocean water it produces acid fumes - known as "laze" - which are a mix of hydrochloric acid gas, steam and tiny volcanic glass particles.
The USGS said: "This hot, corrosive gas mixture caused two deaths immediately adjacent to the coastal entry point in 2000, when seawater washed across recent and active lava flows."
It added that the acid produced is around as corrosive as diluted battery acid.
Dozens of homes have been burned by the lava and thousands of people have had to flee since Kilauea began erupting more than two weeks ago.
Lava continues to spew out of large cracks in the ground which formed in residential neighbourhoods in a rural part of the Big Island.
The rate of sulphur dioxide gas emerging from the cracks has tripled after an eruption on May 17th, which the USGS said shot lava 9,144 metres into the air.
Hawaii County has had to repeat air quality warnings, with families heading to evacuation centres to get free face masks.
On Saturday a man suffered a broken leg after he was hit by lava as he stood on his third-floor balcony.
"The lava hit him on the shin and shattered everything from there down on his leg," Janet Snyder, Hawaii County mayor's spokesman told Hawaii News Now.
Officials said lava thrown from the volcano can weigh as much as a fridge and even small pieces can be lethal.
The US Coast Guard has enforced a safety zone extending 300 metres from where the lava has entered the ocean.
Coast Guard Lt Cmdr John Bannon said "getting too close to the lava can result in serious injury or death".
"Like typical eruptions and lava flows, it's really allowing Madam Pele to run its course," Hawaii Governor David Ige said, referring to the Hawaiian goddess of volcanoes and fire.
Over the weekend the lava began to move more quickly and emerge from the ground in greater volumes.
Since Kilauea began erupting on 3 May, around 40 structures - including two dozen homes - have been burned to the ground.
Around 2,000 people have been evacuated from their homes, including 300 who are staying in shelters.
Scientists explained that is because the lava which first erupted was magma left over from a 1955 eruption which had been stored in the ground for the past six decades.