I think the main fuel additive used in Europe is (or was until recently) ETBE, or ethyl tertiary-butyl ether. This additive is similar to MTBE (methyl tertiary-

I think the main fuel additive used in Europe is (or was until recently) ETBE, or ethyl tertiary-butyl ether. This additive is similar to MTBE (methyl tertiary-butyl ether), which was the most popular in the world after lead was outlawed, and continues to be used today in a few countries, like Mexico and Venezuela, but which is very toxic. ETBE appears to not be as toxic, but it is derived from ethanol. In the end it's not clear if it's worth the extra chemical processing step to convert ethanol to ETBE, or to just use ethanol directly. The US chose to use ethanol, and it looks like Europe is moving to ethanol too. [1] https://www.spglobal.com/commodityinsights/en/ci/products/gasoline-octane-improvers-chemical-economics-handbook.html https://www.spglobal.com/commodityinsights/en/ci/products/ga...