Is polyurethane good or bad?

Polyurethane is both good and bad depending on the perspective you take, as it offers major benefits and notable drawbacks. On the good side, polyurethane is extremely durable, versatile, affordable, and protective. It forms a hard, abrasion-resistant film that protects wood floors and furniture from scratches, water, and daily wear, extending the life of products by decades. It is used in mattresses, insulation, car parts, shoes, and faux leather, making modern life more comfortable and efficient. It is easy to apply and provides a beautiful clear finish that enhances wood grain. On the bad side, polyurethane is a petrochemical-based plastic that is not biodegradable, contributes to microplastic pollution as it wears, and during application releases volatile organic compounds and isocyanates that are harmful to respiratory health and require ventilation and respirators. Oil-based versions yellow over time and have strong odors. Manufacturing polyurethane has environmental impacts, and cheap foam can off-gas. So from a performance standpoint, polyurethane is very good, but from an environmental and health during application standpoint, it has significant negatives. Most professionals view it as a useful compromise material that is excellent when used correctly and fully cured.