A protective curable coating containing a polymerization inhibitor, extractable from the cured coating, which is applied to surfaces located above the liquid level of a storage tank containing a polymerizable alkenyl aromatic monomer, e.g., styrene, vinyl toluene, divinyl benzene on which surfaces said monomer tends to condense. The monomer condensing on the surfaces which have been coated extracts some of the inhibitor from the coating and thus polymerization on these surfaces is prevented or substantially restricted.