A lava bomb hit a tour boat in Hawaii, injuring around a dozen passengers, according to a report on CNN and resulting in new restrictions on boats sailing near the erupting Kilauea volcano on Hawaii’s Big Island.

The airborne molten lava penetrated the roof of a boat on a sightseeing tour, leaving a gaping hole and passengers with burns and one woman with a broken leg.

“The explosion looked like a gigantic firework, right off the side of the boat,” said passenger Kirk Olsen to CBS News.

Olsen told the news organization that the boat was approximately 100 yards off the coast of the Big Island when the lava bomb about the size of a basketball broke through the roof of the vessel.

The tour boat was operated by Lava Ocean Tours and is one of several companies that take visitors to see the Kilauea’s lava flow.

The rules governing how close boats could get to the lava flow were recently changed to allow boats as close as 50 meters to the shore but after the incident on Monday, they are required to stay at least 300 meters out.

Tourism has clearly taken a hit on the Big Island since Kilauea’s eruption began, despite the fact that it affects just a small part of the island.

“The bottom line is that there is no reason for travelers to avoid making their vacation plans in the Hawaiian Islands due to safety concerns because of Kilauea volcano,” said Hawaii governor David Ige in May. “Visitors will be welcomed with open arms and treated to the hospitality, aloha, warmth and natural beauty that is found everywhere in Hawaii. The only area to avoid is lower Puna where the eruption is ongoing.”

Travelers will also want to avoid getting too close to the lava flows along the shoreline.