The initial detection of methyl cyanide (CH₃CN) was reported by Solomon et al. in 1971 in Sgr A and B. They used the NRAO 36 foot radio telescope to make their observations. The first extragalactic detection was noted by Mauersberger et al. in 1991. Methyl cyanide was also observed in Comet Kohoutek by Ulich and Conklin.

UPDATE (July 2018): Methyl cyanide was detected in the protoplanetary disk MWC 480 by Öberg et al. in 2015.

Methyl cyanide or acetonitrile is poisonous, but it is not as toxic as HCN.