A vegetable oil-based electrically-insulating fluid. This fluid is environmentally-friendly and has a high flash point and a high fire point. The base oil is hydrogenated to produce maximum possible stability of the oil, or alternatively, is a higher oleic acid oil. The vegetable oils of the preferred embodiments are soybean or corn oils. The oil can be winterized to remove crystallized fats and improve the pour point of the base oil, without the necessity of heating the oil. The base oil can also be combined with an additive package containing materials specifically designed for improved pour point, improved cooling properties, and improved dielectric stability. The fluid is useful in electrical components such as transformers and transmission lines. The invention also provides methods for making the fluid and fluid-filled electrical components.