Well, we don't have MTBE, but we still have oygenates, primarily ethanol. Renewable standards made it spill over to conventional gasoline as well. RBOB and then CBOB. Probably the components people thinks smell so good are the aromatics (benzene, toluene, xylenes) which have been reduced significantly over the years, starting in CA, but everywhere since the MSAT regs.NO! In 2005, Congress passed the Energy Policy Act that removed the oxygenate requirement for reformulated gasoline (RFG) Its use also declined in the United States in response to environmental and health concerns.
And just to be clear, MTBE was in gasoline throughout the US, not just in California.