In chemistry there is a whole class of substances known as alcohols.

The story begins with a substance known in the game as black fog.

Our new plant here will deal safely with this substance, known as oxide.

Such has repeatedly been the case with children's exposure to lead, a substance known since 1923 to damage the brain.

Whatever it is, it's arguably the worst substance known to man.

So one has to use that delicate substance known as physical intuition.

Cyanide is one of the most toxic substances known to man.

It's one of the most dangerous substances known to man.

"It is the single most toxic substance known to man."