Lava tourism is a significant local industry, and the Coast Guard has previously imposed similar limitations for tour boat operators at Kilauea's Kamokuna ocean entry.
Civil defence notices cautioned motorists, boaters and beachgoers to beware of caustic plumes of "laze" formed from two streams of hot lava pouring into the sea after cutting across Highway 137 on the south coast of Hawaii's Big Island late on Saturday and early Sunday.
First it was catastrophic lava.
May 6, 2018: The governor of Hawaii declared a local state of emergency near the Mount Kilauea volcano after it erupted following a 5.0-magnitude natural disaster, forcing the evacuation of almost 1,700 residents.
Lava from the volcanic eruption oozed out to the ocean on Saturday, creating something called "laze", a lava-haze hybrid. As the lava combines with ocean water, it forms a steam cloud laced with hydrochloric acid and fine particles of glass.More news: Republican infighting over immigration spills over with farm bill collapse
Geological Survey scientist Wendy Stovall says the plume is slightly off the island's southeast coast and runs parallel to the shoreline. "All waterway users should be aware of the hazardous conditions associated with such an event. Getting too close to the lava can result in serious injury or death", said Lt. Cmdr.
The damage caused by the eruption has spread to much of the Puna region but the Civil Defense Authority has warned that stronger trade winds could blow the toxic ash cloud out to the rest of the state, affecting millions of other Hawaiians.
The USGS describes laze as a hot and corrosive gas mixture.
Bush fires have also been reported, Johnson said, adding smoke to the airborne health hazards.
"We have no way of knowing whether this is really the beginning or toward the end of this eruption", said Tom Shea, a volcanologist at the University of Hawaii.
The volcano has opened more than 20 vents, including four that have merged into one large crack. It has been gushing lava high into the sky and sending a river of molten rock toward the ocean at about 300 yards (274 meters) per hour.More news: Warriors breeze past Rockets in game three
The eruptions have also created a phenomenon known as "vog"-a combination of water, carbon dioxide, sulfur dioxide, dust and fine particles, which can cause irritation to the lungs, especially in people who suffer from respiratory problems".
A giant eruption at the Hawaii volcano Kilauea last week saw huge plumes of volcanic ash spiraling more than six miles into the air.
"A handful of old fissures have reactivated and joined together over the past few days", CNN's Scott McLean reported from Pahoa.
Members of the media record a wall of lava entering the ocean near Pahoa.
Dozens of homes have been burned by the lava and thousands of people have had to flee since Kilauea began erupting more than two weeks ago. A magnitude 5.0 natural disaster had just been recorded before the explosion on May 3, according to the Associated Press.More news: Trump Demands DOJ Probe of Federal Bureau of Investigation