Lava Ocean Tours, the lava boat operator whose 23 passengers were injured Monday morning by lava bombs, had a prior history of passenger lawsuits and had been previously fined by the state for lava tour boat violations.

The U.S. Coast Guard and the state Department of Land and Natural Resources, the Hawaii Police Department and the Division of Conservation and Resources Enforcement are investigating the latest incident, which occurred when a lava bomb — a little larger than a basketball — exploded into the air and crashed through the boat’s metal roof.

A 20-year-old woman, whose leg was seriously injured in the incident, was still hospitalized at The Queen’s Medical Center on Tuesday. Hilo Medical Center said the rest of the injured passengers were treated and released Monday.

Concurrent investigations will determine whether Lava Ocean Tours, its head captain Shane Turpin or crew members were under the influence of drugs or alcohol or violated any state or federal boating laws. They also will determine whether the vessel was seaworthy and whether all mariners involved were properly licensed and credentialed.

Investigators will evaluate whether the current safety range — which allows certified lava boat tours to come within 300 meters of the lava’s entry point — is sufficient, and potentially could consider whether commercial lava boat tours should be suspended, said Coast Guard Chief Petty Officer Sara Muir.

Muir said the 300-meter safety zone was established in March, but an exemption was granted July 11, giving Lava Ocean Tours entry approval to come within 50 meters of the lava’s ocean entry point. That exemption was rescinded Monday after the lava bomb incident.

Muir said entry approvals have been awarded on a case-by-case basis since commercial operators objected to the blanket 300-meter safety zone during public meetings.

“It’s changed a few times. Fifty meters is the closest it’s been,” she said. “We are saying this is the minimum safe distance, but keep a keen eye out. We expect all mariners to use good judgment in a dynamic situation when they are on the water.”

Muir said the 50-meter entry approval request was granted by the captain of the port after input was sought from officials at partner agencies, including the U.S. Geological Survey, the Hawaiian Volcano Observatory, the National Oceanic and Atmospheric Administration and the University of Hawaii.

Hawaii Mayor Harry Kim said Tuesday in an interview on Hawaii News Now that he did not know the safety zone had been reduced to 50 meters, and he supports maintaining a 300-meter safety zone. Turpin’s competitors say they didn’t support a 50-meter safety zone for that area, either.

Ikaika Marzo, owner of Kalapana Cultural Tours, said he also had permission to take his vessel the Ohana to within 50 meters of the flow, but that unlike Turpin he didn’t exercise that prerogative. Marzo said the other two permitted lava boat companies, Moku Nui Lava Tours and Hawaiian Lava Boat Tours, which share his boat, also kept greater distances.

“We didn’t think it was safe. I called the Coast Guard to complain,” Marzo said. “We never got any closer than 150 meters in that area. I felt 50 meters was too risky where the lava was really going in. We were witnessing explosions there every day.”

All the lava boat tour companies were operating Tuesday. Turpin’s second boat was back in the water continuing tours.

Muir said the boat hit by the lava bombs, the Hot Spot, will have to be repaired and go through sea trials before it can resume commercial operations.

Marzo said business was robust Tuesday, but he and the operators of Moku Nui Lava Tours and Hawaiian Lava Boat Tours fear the incident could have lasting repercussions. They worry that the 300-meter limit will dampen demand if it is routinely imposed. They also fear that they’ll be shut down.

“We’re big-time worried about getting shut down,” Marzo said. “Our track record is good. None of us have had any incidents in six or seven years of operations. But (Lava Ocean Tours) has a whole lot of incidents.”

Turpin did not return calls from the Honolulu Star- Advertiser on Monday or Tuesday.

Toni Marie Davis, executive director of the Activities & Attractions Association of Hawaii, said Turpin is a member in good standing and that the boat “was at the wrong place at the wrong time.”

Court records show that the company previously settled at least three civil cases, involving incidents going back some six years. One of the cases, filed in February in U.S. District Court for the District of Hawaii, involved an Italian passenger, Robert Cocco, who took a sunset lava tour Sept. 30, 2016. In the document, Cocco alleged that he sustained serious injuries, including a fractured vertebra, when the boat traveled at a high rate of speed through rough waters. The suit alleges that Lava Ocean Tours and Turpin were motivated by financial gain and “acted outrageously, and were guilty of gross negligence, willful, wanton and reckless indifference.”

Another case, filed in 2015 in the District Court, involved a Japanese passenger, Kimiko Noura, who brought suit against Lava Ocean Tours and Turpin for a Feb. 17, 2013, incident aboard the LavaKai tour boat, where she fell and suffered a pelvic fracture and foot sprain. The suit alleges that Turpin operated the vessel with “willful or wanton disregard for the safety of persons or property.”

A Chinese visitor, Michael Bin Wu, also sued Turpin and his previous company Lava Ocean Adventures LLC in 2014 in District Court for an incident that allegedly happened Dec. 30, 2012. Wu claimed the boat was traveling at “unsafe speed in rough ocean conditions” and that he was “thrown up in the air and then back down onto the unpadded metal seat,” sustaining severe injuries to his low back, right hip and thigh.

DLNR also said Tuesday that it had previously fined Turpin $15,000 for launching the vessel LavaKai II from the Pohoiki boat launch ramp three times without a required commercial use ramp permit from Feb. 3 to 7, 2017.

Complaint in a civil action: Summons by Honolulu Star-Advertiser on Scribd

Complaint for damages; demand for Jury trial by Honolulu Star-Advertiser on Scribd

Complaints; summons by Honolulu Star-Advertiser on Scribd

Star-Advertiser reporter Leila Fujimori contributed to this report.