A polyurethane spraying system minimizes emissions of a polyisocyanate while spraying a mixture of a polyisocyanate and a resin composition onto a surface. The system includes a first reactant supply tank including the resin composition. The system also includes a second reactant supply tank including the polyisocyanate. The system further includes a non-gaseous pump that is coupled with the first and second reactant supply tanks, a mixing apparatus that is coupled with the first and second reactant supply tanks for mixing the resin composition and the polyisocyanate prior to spraying, and a particular spray nozzle that is coupled with the mixing apparatus. The polyurethane spraying system produces less than 50 parts of the polyisocyanate per one billion parts of air according to the NIOSH 5521 Impingement Method while spraying the mixture onto the surface.