FR3 insulation oil is a flame-retardant natural ester insulation coolant used in power equipment such as distribution transformers. It has excellent environmental performance, fire safety, chemical performance, and electrical performance. FR3 insulating oil is composed of edible vegetable oil and food grade performance enhancing additives. This insulating oil does not contain any petroleum, halogens, silicone resin or any other suspicious materials, and can be quickly and thoroughly biodegraded in soil and aquatic environments. The aquatic toxicity test shows that this insulating oil is non-toxic. The insulating oil is green, fully demonstrating its environmental characteristics.