Authorities on Sunday warned the public that as molten rock from Kilauea volcano poured into the ocean, a toxic steam cloud has formed due to a chemical reaction when lava touches seawater.
Scientists said the acid in the plume was about as corrosive as diluted battery acid.
The hazardous cloud billowing from where lava is pouring into the ocean off Hawaii's Big Island may spread as far as 15 miles downwind.
Scientists said the steam clouds at the spots where lava entered the ocean were laced with hydrochloric acid and fine glass particles that can irrigate the skin and eyes and cause breathing problems.
The lava haze, or "laze," from the plume was just offshore and running parallel to the coast, said U.S. Geological Survey scientist Wendy Stovall.
Getting hit by it might feel like being sprinkled with glitter.
"If you're feeling stinging on your skin, go inside," Stovall said. Authorities warned that the plume could shift direction if the winds changed.
Kilauea has burned some 40 structures, including two dozen homes, since it began erupting in people's backyards in the Leilani Estates neighborhood on May 3. Some 2,000 people have evacuated their homes, including 300 who were staying in shelters.
Joseph Kekedi, an orchid grower who lives and works about 3 miles from where lava dropped into the sea, said luckily the flow didn't head toward him. At one point, it was about a mile upslope from his property in the coastal community of Kapoho.
He said residents can't do much but stay informed and be ready to get out of the way.
"Here's nature reminding us again who's boss," Kekedi said.
In recent days, the lava began to move more quickly and emerge from the ground in greater volume. Scientists said that's because the lava that first erupted was magma left over from a 1955 erupted that had been stored in the ground for the past six decades.
The molten rock that began emerging over the past few days was from magma that has recently moved down the volcano's eastern flank from one or two craters that sit further upslope -- the Puu Oo crater and the summit crater.
The new lava is hotter, moves faster and has spread over a wider area.
Gov. David Ige told reporters in Hilo that the state was monitoring the volcano and keeping people safe.
"Like typical eruptions and lava flows, it's really allowing Madam Pele to run its course," he said, referring to the Hawaiian goddess of volcanoes and fire.
A man was seriously injured when he was hit with lava spatter while standing on his third-floor balcony — the first known injury related to Hawaii’s Kilauea volcano eruptions as new volcanic activity creates new threats in surrounding neighborhoods.
The homeowner on Noni Farms Road in Pahoa was hit with lava on the shin and taken to the hospital with serious injuries, Janet Snyder, spokeswoman for the Office of the Mayor, told Reuters.
"It hit him on the shin, and shattered everything from there down on his leg," Snyder said, adding that the lava spatter could weigh “as much as a refrigerator.”
“And even small pieces of spatter can kill,” she said.
Fox News' Edmund DeMarche, Katherine Lam and The Associated Press contributed to this report