The simplest two carbon alkyne with the formula HCCH.
https://reptox.cnesst.gouv.qc.ca/pages/fiche-complete.aspx?no_produit=497&nom=Acétylène Canada toxicological data sheet acetylene
--- https://reptox.cnesst.gouv.qc.ca/pages/fiche-complete.aspx?no_produit=6023&nom=Carbure+de+calcium Canada French acetylene calcium carbide toxicological data sheet
--- http://www.inrs.fr/accueil/produits/bdd/doc/fichetox.html?refINRS=FT%20212 France French acetylene acetylene acetylene acetylene acetylene occupational exposure occupational diseases reference values guidelines toxicological data sheet