Used primarily in electrical equipment as a dielectric fluid in transformers and capacitors due to its chemical stability and insulating properties. Also found in heat transfer systems and as a plasticizer in polymers to improve flexibility and durability. Historically used in pesticide formulations as a carrier or additive to enhance persistence. Its high resistance to degradation made it useful in industrial applications, though environmental and toxicity concerns have led to significant restrictions. Occasionally used in research settings to study persistent organic pollutants and their impact on ecosystems and biological systems.