What material spews out of the volcano?

When a volcano erupts, ash, smoke, lava and many other solid, liquid, volcanic bombs and gases. When the volcano erupts, lightnings can also be formed. In the gases bit, they spew out mostly steam, but poisonous gases: carbon monoxide, Sulfur dioxide, carbon dioxide, hydrogen chloride escapes as well, and can suffocate people even before the ash hits them.It depends on how molten lava is ejected and rocks.

-Jiayu-