Residents on the Big Island of Hawaii were alerted on Thursday to rising levels of toxic gas from lava-oozing fissures, and geologists warned that new areas east of the erupting Kilauea volcano may be at risk of molten rock bursting from the ground.

If Hawaii's Kilauea volcano blows its top in the coming days or weeks, as experts fear, it could hurl ash and boulders the size of refrigerators miles into the air.

What you need to know about the volcano eruption in Hawaii.