A Methyl Methacrylate storage tank likely suffered a structural rupture that initially presented as a sharp-smelling gas leak before escalating into a severe runaway polymerization reaction. This spontaneous chain reaction quickly consumed the free monomer, generating immense pressure that the non-pressure vessel could not contain. The incident underscores the critical importance of properly dispersing and monitoring chemical inhibitors in bulk storage to prevent highly reactive liquids from spontaneously polymerizing.