Frequently asked questions

Q: What is a natural ester?  What is a synthetic ester?

A: From IEEE Standard C57.12.80-2010 IEEE Standard Terminology for Power and Distribution Transformers.

3.268 natural ester fluid: A specially refined and formulated seed-oil (vegetable oil) based dielectric fluid for insulating and cooling electrical equipment for indoor and outdoor installations, which generally conforms to ASTM D6871 when new.

3.438 synthetic ester insulating fluid: A specially formulated polyol ester based less-flammable insulating fluid and coolant for use in fire-resistant indoor and outdoor transformers.

Q: How do natural esters differ from mineral oil?

A:  First, natural esters are vegetable-based.  They have twice the flash and fire point as mineral oil so it is less likely to start on fire.  In fact, there has not been a reported fire-related failure an FR3 fluid-filled transformer since the product was launched.  In addition, the fluid is self-extinguishing so there is no chance of a pool fire.

Second, it has a better environmental footprint as it is ultimately biodegradable, carbon neutral and non-toxic and non-hazardous in soil and water.

Third, its ability to absorb water helps slow the aging process in insulation paper thus protecting the insulation system and extending the asset life of the transformer.

Fourth, with the standardized high temperature capability, transformers filled with FR3 fluid can operate 20C warmer than mineral oil filled transformers without accelerating the aging rate of the solid insulation system.  This capability provides utilities with the flexibility to increase overload capacity up to 20%, extend asset life or a combination.

Q:  Do esters work in both power and distribution transformers?

A:  Yes.  There is a proven track record of distribution and power transformer installations through 420kV.

Q:  Does FR3™ natural ester fluid and Envirotemp™ 200 synthetic esters comply with industry standards?

A:  Yes, both FR3 natural ester fluid and Envirotemp 200 synthetic ester fluid comply with IEEE and IEC standards.

Q:  Why did Cargill participate in the U.S. Environmental Protection Agency’s (EPA) Safer Choice program?

A:  Cargill’s FR3™ natural ester fluid has many environmental benefits. For utilities and organizations who specify FR3 fluid for their transformer fleets, they can enhance their sustainability efforts and improve the fire and environmental safety for the communities they serve. The U.S. EPA Safer Choice program is an important designation for companies who seek to incorporate safer products into their organization.

Cargill’s FR3™ natural ester dielectric fluid has earned the U.S. Environmental Protection Agency’s (EPA) Safer Choice label by meeting the rigorous criteria of the Safer Choice program. Safer Choice works with manufacturers to develop safer products that meet high performance standards. The Safer Choice label allows purchasers to quickly identify and choose effective products that help protect the environment and are safer for people. We’re proud to announce that FR3™ natural ester dielectric fluid carries the Safer Choice label.

Q:  What is the U.S. Environmental Protection Agency’s (EPA) Safer Choice program?

Program Benefits
The Safer Choice label helps consumers and commercial buyers find safer cleaning and other products that are safer for people, families, workers, pets, and the environment. Products with the Safer Choice label help consumers and commercial buyers identify and select products with safer chemical ingredients, without sacrificing quality or performance.

Technical Rigor
EPA scientists and experts in the Safer Choice program, as well as qualified third-party reviewers, evaluate every ingredient in a product to assess its potential to cause human or environmental health effects. To carry the Safer Choice label a product must meet the Safer Choice Standard which includes requirements for safer chemical ingredients, performance, ingredient disclosure, packaging, VOCs, and pH. If a product does not meet the Safer Choice Standard, Safer Choice scientists work with manufacturers to identify safer ingredients. As a resource to manufacturers and the public, EPA lists chemical ingredients that qualify for Safer Choice products on the publicly available Safer Chemical Ingredients List (SCIL) (

To learn more about the program, please visit

Endorsement Disclaimer
EPA/Safer Choice recognition does not constitute endorsement of this product. The Safer Choice label signifies that the product’s formula, as Cargill, Inc., has represented it to the EPA, contains ingredients with more positive human health and environmental characteristics than conventional products of the same type. EPA/Safer Choice relies solely on Cargill, its integrity and good faith, for information on the product’s composition, ingredients and attributes. EPA/Safer Choice has not independently identified, that is, via chemical analysis, the ingredients in the product formula, nor evaluated any of Cargill’s non-ingredient claims. EPA/Safer Choice provides its evaluation only as to the product’s human health and environmental characteristics, as specified in the Safer Choice Standard and based on currently available information and scientific understanding.

Q:  When did Cargill purchase the dielectric fluid business from Eaton’s Cooper Power Systems?

A:  Cargill collaboratively developed the FR3 fluid product with Eaton’s Cooper Power Systems for the past decade.  In July 2012, Cargill purchased the Envirotemp dielectric fluid business which included FR3 natural ester fluid.

Q:  Do you sell FR3 fluid to other transformer manufacturers?

A:  Yes.  We take a collaborative approach in working with transformer manufacturers and their utility customers to develop the right transformer solution for their particular needs.

Q:  Who do I call if I have questions?

A:  Please start with our customer service team at 1-800-842-3631 or contact the appropriate region below:

North America
+1 800-842-3631

+65 6393 8552

+55 11 5099 3458


+31 20 500-6695

+ 91 124 409-0489

+90 216 554-18-00