AVGAS is a gasoline containing tetra-ethyl lead (TEL), which gives it a high octane number. This allows the fuel to be used in engines with higher compression ratios without detonating, which can damage the structure of the combustion chamber.

The EU has put the additive Tetraethyllead (TEL) on the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) list with a deadline of May 2025. After the deadline, TEL may no longer be imported into the EU, thus preventing the production of AVGAS 100 LL in the European refineries. The US government intend to ban AVGAS 100 LL by 2030 and commenced the related legislation in February this year. It is unknown how long Innospec, a UK based company, intends to continue to produce TEL if it is banned in the USA.

Owners of an aircraft with a type certificate to operate only on AVGAS 100LL are being advised going forward to check with their maintenance organisation whether alternative options are available for their aircraft.