Biodegradable Insulating Liquid
Another high voltage insulating liquid is Envirotemp® FR3® manufactured by Cooper Power Systems. It is a transformer fluid made from soybeans, and is biodegradable. It does not contain any petroleum, halogens or silicones. It is fire resistant, and is currently used in both indoor and outdoor transformers. Its dielectric strength is rated at 56kV for a 2.0mm gap.
Environmentally friendly insulators such as this could be good for products that are WEEE compliant. (Waste Electrical and Electronic Equipment directive 2002/96/EC.)