King James Version
By these three was the third part of men killed, by the fire, and by the smoke, and by the brimstone, which issued out of their mouths.English Standard Version
By these three plagues a third of mankind was killed, by the fire and smoke and sulfur coming out of their mouths.New International Version
A third of mankind was killed by the three plagues of fire, smoke and sulfur that came out of their mouths.