The Coast Guard is ramping up efforts to stop illegal charter boat operations near where lava is entering the ocean off Hawaii island out of a concern for visitor safety.

The additional enforcement is in response to the recent increased interest in the ocean entry from Kilauea Volcano, said Coast Guard Petty Officer 2nd Class Melissa McKenzie.

Since Tuesday, the Coast Guard identified two tour boats operating illegally — both for operating a charter boat without a license to carry paying passengers and without a state license to operate out of Pohoiki Boat Ramp, McKenzie said.

Coast Guard boarding officers boarded the vessels and put a stop to the voyage after discovering the violations, she said. The cases against the two vessels are ongoing.

Capt. David McClellan, chief of prevention for the Coast Guard in Hawaii, said safety is the top priority.

“For boat operators, it is important to maintain situational awareness and not unnecessarily put yourself, your passengers or your boat in danger,” he said.

“For visitors, it’s important they check that their hired boat operators are licensed ensuring they possess the experience and training required to get them to the viewing area and back safely,” he continued.

Commercial tour boat operators must possess appropriate merchant mariner credentials to operate. Masters of commercial charters are also required to keep a state permit on board.

Vessels for hire carrying less than 7 passengers must have a Coast Guard operator of uninspected passenger vessel license. Larger vessels must have a Coast Guard-issued certificate of inspection posted in a visible location.

The spot where lava meets the ocean is one of the most dangerous areas of Volcano National Park because the lava bench could potentially collapse, sending dangerous projectiles into the air, the Coast Guard said. The steam also contains hydrochloric acid and glass particles.

The Coast Guard urged tour boat operators to maintain a safe distance from both to ensure the safety of their passengers.