Hawaiian County Civil Defense Agency warned residents to "shelter in place" as a result of the drifting ash plume.
Part of the U.S. Geological Survey's Volcano Hazards Program, the Hawaii Volcano Observatory is perched on the rim of Kīlauea's summit caldera. A change in prevailing winds blew the volcanic smog, or vog, north toward the next island, Maui.
The Kilauea eruption is the latest since the Hawaii volcano began spewing ash and lava earlier in May, as fissures opened up along the volcano.
Scientists warned on May 9 that a drop in the lava lake at the summit might create conditions for an explosion that could fling ash and boulders the size of refrigerators into the air.
The volcano on the Big Island exploded at about 6am.
"The Big Island is going to have a lot of vog today and maybe Maui", National Weather Service meteorologist Matt Foster said.
GettyHawaii volcano eruption Plumes of smock and ash measure over 30,000 feet in the air
The US Geological Survey (USGS) said in a statement microwave-sized "ballistic blocks" had been recovered after being propelled out of Kilauea - sparking fears of an imminent explosive eruption.
People watch as ash erupts from the Halemaumau crater near the community of Volcano during ongoing eruptions of the Kilauea Volcano in Hawaii, U.S., May 15, 2018.
Ash is not poisonous but irritates the nose, eyes and airways.
Residents also have to worry about sulfur dioxide gases emitted from the lava flows.
Before-and-after satellite images are giving a new look at the lava from Hawaii's Kilauea Volcano. Almost 40 structures have been destroyed as a result of the eruptions, but no deaths or injuries have been reported.
A looming menace remains the risk of an "explosive eruption" of Kilauea, an event last seen in 1924. They say a phreatic eruption could happen, sending ash plumes as far as 12 miles from the summit crater.