What are the impacts to vehicle seals with higher dosages of fuel ethers?

Ethers such as MTBE have been commercially used in petrol for more than 40 years.  While alcohols blended into petrol at higher concentrations and under certain conditions may present a compatibility issue with some materials found in the vehicle fuel systems, the ether versions of the same alcohols will usually be much more compatible with the metals and the non metals (elastomers and plastics) that are commonly found in the vehicle fuel systems and fuel distribution systems.

Compatibility with non-metal materials has the potential to become an issue as the concentration of oxygenates (alcohols and ethers) are increased in fuels as a means of reducing the dependency on crude oil for producing transportation fuels. Various elastomers, rubbers and plastics are used by OEM (original equipment manufacturers) for sealing and containing liquid fuels in closed systems such as automotive vehicles, non-automotive small engines, bulk fuel storage and fuel distribution systems. The performance properties of some elastomers may alter when in contact with fuels containing higher volume concentrations of some oxygenates which can then contribute to higher permeation of evaporative VOC emissions (volatile organic compounds) and possibly shorter service life (lower durability).