The Kilauea volcano on the Big Island of Hawaii has been erupting since May 3, and the lava flow has destroyed 40 structures and made many roads inaccessible. But the molten rock itself is not the only risk.
Three separate lava flows have now reached the sea, each causing a toxic plume of gas to rise.
When lava hits seawater, a chemical reaction happens that produces hydrochloric acid — the acid in your stomach that breaks down food. At the same time, the seawater rapidly cooling the lava (which is about 2,100 degrees Fahrenheit), resulting in the instant formation of tiny glass particles.
The glass particles then travel upward in the cloud of steam and hydrochloric acid. If you go near that cloud, you could be breathing in glass.
Thanks to mandatory evacuations in the area, this lava haze, or "laze," as volcanologists call it, shouldn't harm anyone. Most of the time, laze doesn't travel more than a couple of miles before it dissipates.
Because this eruption has gotten so much news coverage, and because many people who live in the mainland U.S. don't have a good concept of how big Hawaii actually is, it may seem like the entire island of Hawaii is covered in lava right now.
But as the below graphic shows, the affected area is actually quite small.
The volcano has been erupting for four weeks and does not show any signs of stopping. Over 2,000 people have been evacuated already, and more evacuations may be necessary.
Residents of the Hawaiian neighborhood of Puna only have one remaining escape route from the eruption area, and that's State Highway 130. Lava may soon run across the highway.
Or, magma underneath the surface could open cracks in the road. The U.S. Marine Corps has helicopters ready to evacuate residents, should that happen.