Commonly Asked Questions about Ethos FR1. What is Ethos FR?Ethos FR is a product that is added to fuels to make engines burn fuel more completely. Ethos FR is non-toxic, non-hazardous and works with any fuel used in cars, trucks, buses, ships, trains and generators. Ethos FR is free of carcinogens and is not derived from petroleum. It utilizes cleaning and lubricating esters suspended in a