Detecting odors of toxic substances

[Garlic]

How are odors of extremely toxic chemicals be detected? If the chemical doesn't contain any of the common molecules with an odor, can we analyse how it would smells like?
And can we predict how a certain substance smells like? (without even analysing it)
How do we know, for example, that methyl isocyanate has a "sharp, pungent odor"?

 

[Borek]

How do we know, for example, that methyl isocyanate has a "sharp, pungent odor"?

From the people who smelled it and lived long enough to report.

And I am deadly serious.

 

[Garlic]

This is... unbelievable

 

[DrDu]

Take in mind that the nose is sometimes incredibly sensitive to smells. You would have to expose a person for several hours to smellable concentrations of methyl isocyanate for it to be lethal.

 

[Kevin McHugh]

The nose is very sensitive to poisonous vapors. For instance, the nose can detect c.c. 3 ppm of H₂S gas. with the exception of methane and carbon monoxide, most lethal chemicals have pungent odors.