A volcanic explosion sent a “lava bomb”through the roof of the vessel.
The Hawaii County Fire Department, confirmed the incident occurred early Monday morning.
The lava bomb punctured the roof leaving a large gaping hole in the vessel and damaging one of the boat’s railings.
The boat returned to its origin of Wailoa Harbor in Hilo around 7 a.m local time (18.00 BST).
Those aboard the boat had varying degrees of injuries, with three people taken to Hilo Medical Center for further treatment.
Two of the hospitalised passengers were reported to be in a stable condition, including a woman in her 20s, was in serious condition with a fractured femur.
The remaining passengers drove themselves to the hospital.
The Hawaii fire service reported that their injuries were superficial.
Kua ‘o Ka La Public Charter School was destroyed by lava last week, along with nearby Ahalanui Beach Park.
The continual eruptions of Moutn Kilauea on Big Island have changed Hawaii’s natural landscape forever.
Recently, explosions at the summits of the mountain caused tremors akin to 5.2 magnitude earthquakes across the region.
The Hawaii Civil Defense Agency confirmed that a basketball sized lava ball burst through the ships exterior.
Taking to Facebook, the agency posted: “Early Monday morning, 23 passengers on a lava tour boat were injured when an explosion at the ocean entry
hurled lava bombs and debris onto their boat.
“Of the injured, 4 were taken by ambulance, one seriously injured with a fractured femur. Most of the injured passengers had superficial injuries and were treated on arrival at Wailoa Harbor in Hilo.”
“A basketball-sized lava bomb punctured the vessel’s roof, and explosion debris littered the floor of the boat.”
According to CNN, a witness who saw the boat after the explosion said there were rocks all over it, and some people leaving the boat had burns and gashes on their legs.
In the weeks previous to the incident, the US Geological Survey has warned of the danges of lava mixing with sea water.
Lava channels continue to make their way to the Pacific from Fissure 8, which has remained highly volatile since Kilauea’s original eruptions in May.
On its website, the company running the tour said: Lava Ocean Tours Big Island lava boat tours are an exciting way to experience the molten hot lava entering the sea. See, Hear & Feel the heat from your front row seat onboard one of our world class catamarans.”
The people were aboard a tour boat that takes visitors to see lava plunging into the ocean. Several companies operate such tours.
Over the weekend, it emerged a new island had formed in the Pacific, made of lava, as the dedly substance mixes with sea water to produce Laze, a corrosive and toxic substance that causes respatory conditions.
U.S. Geological Survey volcanologist Wendy Stovall told USA Today that lava bombs occur when water interacts with lava. The water flashes to steam, which causes the lava to explode into fragments, she said.
The boat reportedly holds 49 people, but it was unknown how many people were on board at the time of the incident.