A polyurethane foam is disclosed and described. The polyurethane foam is formed by combining a first component comprising at least one polyol with a second component comprising at least one polyisocyanate. The ratio of the number of isocyanate equivalents in the second component to the number of hydroxyl equivalents in the second component is less than 1.0. The foam exhibits low levels of free diisocyanate monomer, thereby reducing the amount of hazardous, volatile organic compounds. As a result, the foam can be prepared and installed without the need for ventilation equipment, external sources of fresh air, and the like.