Hilo >> Hawaii’s lava boat tour industry had a rough day — literally — Wednesday, two days after an explosion beneath the surface of the ocean hurled hot rocks like mortars that injured 23 passengers during a ride off Kapoho Monday.

Rough ocean conditions led three of Hawaii island’s four permitted lava boat tour companies to cancel trips Wednesday.

The fourth operator, the Lava Ocean Tours company involved in Monday’s accident that left one woman with a fractured femur after a roughly basketball-sized rock crashed through the metal roof of its boat HotSpot, was the only one to take passengers out on an evening trip in unfavorable seas.

“This is a bumpy ocean out here,” Sky Mullins, a Lava Ocean Tours captain, advised ticket holders before boarding and motoring away from a dock at Wailoa Harbor in Hilo with a full load of 46 passengers aboard another company boat, Lavaone.

Several passengers said they were aware of Monday’s accident but weren’t deterred.

Shun Naganuma, a visitor from Japan who booked the tour with his girlfriend, said he thought about asking for a refund. “But we are excited, so we go as scheduled,” he said, adding that his expectation of the tour was 50 percent exciting and 50 percent scary.

Mike Johnson from San Francisco said he weighed the risk of another accident happening and figured “the odds of two (accidents) happening in a small period of time are pretty slim, and plus I’m sure all the safety people are out there right now, so it’s probably one of the safer times to go.”

Rocky Koga of Los Angeles, who was on the Big Island for a business meeting in Waikoloa with others including Johnson, also wasn’t dissuaded.

“I have life insurance and I haven’t told my wife, so I’m all safe,” he said.

Moshe Shani, a visitor from Israel, took his wife and son on the tour with no hesitation. “It’s a once-in-a-lifetime event,” he said.

Captain Mullins gave everyone a chance to back out with a refund before explaining that a bumpy ride was ahead and saying that the frail, injured, pregnant or anyone who was scared might not want to go.

Mullins didn’t mention Monday’s accident, and stated that the only way people get injured on a boat in Hawaii is because they don’t hold on properly. “We’re going to get you back here safe and sound,” he said.

Every one of the passengers got on the boat.

Ikaika Marzo, owner of lava tour operator Kalapana Cultural Tours, said he and other companies have to build the lava tour name back up after the incident with Lava Ocean Tours. He said seven customers called Wednesday to cancel.

Marzo also is concerned that government regulators could decide to shut down the industry.

“One sour apple spoils it for the whole bunch,” he said.

A possible factor in Monday’s accident was how close the U.S. Coast Guard allows tour boats to get from the lava entry into the ocean. On July 11, the agency relaxed a 100-meter boundary to 50 meters for Lava Ocean Tours after that company requested a change. For a long time, the minimum distance was 300 meters.

Marzo said 50 meters was too close and said he complained to the Coast Guard about that while explaining that so-called “lava bombs” have been getting blasted out of the ocean daily inside of 100 meters of shore since lava entered the ocean around Kapoho more than a month ago.

Marzo said his company stayed at least 100 or 150 meters away because being closer was too risky in his judgment.

“It’s like Russian roulette you’re playing (inside 100 meters),” he said.

The Coast Guard re-instituted the 300-meter boundary after the accident, which sidelined the Lava Ocean Tours boat HotSpot because of damage.

Shane Turpin, the owner of Lava Ocean Tours, has not commented to the Star-Advertiser despite requests since Monday.

The Associated Press reported that Turpin said he had taken the HotSpot on Monday to within 250 yards, or about 225 meters, from a lava ocean entry and was headed back out when the explosion happened.

The Hawaii Fire Department reported that Turpin’s boat was about 200 yards from shore when it turned out to sea and an explosion occurred near the shoreline.