OPW Spill Containments are designed to prevent spilled product from entering the soil near the fill and vapor return riser connections during decantation, or in the event of tank overfill. The spill containers catch spillage to help prevent soil contamination and groundwater pollution. The angled ramp design offers superior protection against traffic damage, and provides for secure concrete anchoring. The unique rain shedding design incorporates a seal in the underside of the cover to prevent surface water from entering the spill container.