Only 40% of the population can smell Cyanide. The ability to smell cyanide is genetic.

Cyanide is a deadly poison and people have described it as having a "bitter almond" smell. However, not everyone is capable of smelling cyanide.

Evolutionarily, the ability to smell the "bitter almond" smell of cyanide was an advantage, because the smell warns you away from eating poison. However, most people today don't have this ability.
(source 1, 2)