(CNN) First it was catastrophic lava. Then it was sulfur dioxide. Now Big Island residents have yet another danger to worry about.

Laze -- a mashup of "lava" and "haze" -- is a nasty product formed when hot lava hits the ocean, sending hydrochloric acid and volcanic glass particles into the air.

And now it's a real threat after lava crossed Highway 137 late Saturday night and entered the Pacific Ocean, the Hawaiian Volcano Observatory said.

Laze can cause lung, eye and skin irritation. And it has proven deadly in the past.

"This hot, corrosive gas mixture caused two deaths immediately adjacent to the coastal entry point in 2000, when seawater washed across recent and active lava flows," the HVO said

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