At least 23 people have been injured after lava smashed through the roof of a tour boat following an explosion in Hawaii.

A woman is in a serious condition with a broken thigh bone, the Hawaii County Fire Department said.

She and three others were taken to hospital, while nine other people with superficial injuries drove themselves.

A further 10 people were treated at the harbour.

The lava is coming from the Kilauea volcano, which has been erupting since early May.


A man's leg was broken previously by flying lava.

The boat was taking people to see lava plunging into the ocean. Several companies operate such tours.

The owner and captain of the boat, Shane Turpin, said that he and his tour group had spent 20 minutes about 500 yards offshore without seeing any major explosions from the site where Kilauea's lava enters the ocean.

He said he then navigated his vessel to about 250 yards from the lava and that the explosion came from behind as the ship was leaving the area.

Officials say it can be dangerous to get too close because clouds of acid and fine glass are created sometimes as the lava drops into the water.