N-Nitrosodiethanolamine is primarily utilized in scientific research and analytical chemistry as a reference standard and model compound for investigating nitrosamine formation, detection methods, and carcinogenic mechanisms. It is essential for assessing and quantifying nitrosamine impurities in various products, including cosmetics, pharmaceuticals, lubricants, and petrochemical formulations. Due to its classification as a probable human carcinogen, handling and use are strictly regulated and confined to controlled laboratory settings.