This document discusses vapor emissions from oil-water separators, which are a major environmental problem for oil companies. It introduces VaporVault covers for oil-water separators as a solution. VaporVault covers are made of corrosion-resistant, floatable composite materials. They include individual floatation compartments and vapor-tight seals to control emissions and meet EPA standards. The covers provide an improved method for capturing and containing vapor emissions from oil-water separators.