What are the potential health effects of polyurethane?

The potential health effects of polyurethane depend on exposure type, whether uncured or cured. During application of liquid polyurethane, especially oil-based, health effects include eye, nose, and throat irritation, headaches, dizziness, nausea, and respiratory irritation from volatile organic compounds and isocyanates. Isocyanates are potent respiratory sensitizers that can cause occupational asthma, wheezing, chest tightness, and allergic reactions with repeated exposure, particularly in workers without respirators. Skin contact can cause dermatitis, redness, and allergic rash. Ingestion of liquid polyurethane can cause chemical burns and gastrointestinal irritation. Sanding cured polyurethane creates fine dust that can irritate lungs and cause coughing if inhaled without a mask. For fully cured polyurethane such as on floors after 30 days or in mattresses after off-gassing, health effects are minimal, as it becomes inert, though new foam can off-gas for a few days causing temporary headaches or odor sensitivity in chemically sensitive individuals. Long-term concerns include contribution to indoor dust containing microplastics and potential exposure to flame retardants in some foams. With proper ventilation, respirators, gloves, and allowing full cure time, health risks are low for consumers.