Skorpio, the thing is that it isnt benzonitrile, its an alpha amino nitrile Phe-CH(NR2)CN
What's the difference you say? Like the oldfashioned PCP precursor and contaminant PCC its manufactured from an amine hydrochloride, a ketone or aldehyde and sodium cyanide. With benzonitrile, the nitrile group is stuck to the phenyl group, metabolically. With an alpha amino nitrile, you take your 2C-B-AN and in your body it comes apart into 2C-B, Benzaldehyde and Hydrogen cyanide.
Granted, a 100mg dose only contains about 8mg of HCN, but if inhaled in one breath, only 50mg may cause death.
The body metabolizes cyanide at a steady rate so a 100mg dose of 2C-B-AN will be extremely unlikely to be fatal - but still. Amphetaminil was made to be used in lower doses, some people will binge intensely or sit on large amounts of powder which under unwanted chemical influence could liberate significant doses of HCN, such as when trying to convert it to 2C-B HCl with HCl.
If you're a big fish converting 2.5 kilos of the stuff to 2C-B in a toolshed someplace, you are liberating as much Hydrogen Cyanide as was present in a 200gr tin of Zyklon B, representing an amount deemed sufficent by the Nuremberg trial to gas 50 people, or if acutely ingested representing up to 2000-4000 lethal doses.
Sodium cyanide plant safety video