A chunk of red-hot molten lava from Hawaii's erupting Mt. Kilauea smashed into a tour boat Monday morning, injuring at least 23 people, according to news reports.

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CNN reported that 13 passengers were taken to a hospital and 10 were treated for minor injuries when the boat made it back to Wailoa Harbor on the Big Island and that one woman was seriously injured with a fractured femur.

A photo of the boat when it docked shows a large hole in its roof where the lava bomb slammed into the vessel.

A witness said there were rocks all over the boat and that people had "burns and gashes on their legs," CNN reported.

It’s about an hour’s boat ride from Wailoa Harbor to an area in the vicinity of Kilauea, where lava is flowing into the ocean.

The volcano started erupting in May. Lava has destroyed hundreds of homes in neighborhoods close to it. The U.S. Geological Survey confirmed Kilauea's eruption is still underway.