Methylene diphenyl isocyanate (MDI), (available as pure monomeric 4,4’-MDIs, isomeric mixtures of 4,4’-MDI with 2,4’-monomeric MDI, polymeric MDIs, and modified MDIs), At room temperature is a solid but to manufacture products it is used in a molten form. It is also used primarily to manufacture polyurethane foam used in a .variety of products and industrial applications like: Sponges, Adhesives, Refrigerator parts MDI is toxic if breathed in and can cause coughing, wheezing, chest tightness, or shortness of breath.