Its not common, like the FAQ answer says, in the US. You might be confusing it with MTBE, which is still used in more stringent states. I did that too when I first read it. MTBE is an additive that oxygenates fuel, helping keep the emissions down. Its NOT maganese based, and the HCHII CAN run on it, up to 10% by volume, says so in the manual. But here in California we use a lot of ethanol too, and I think there was just a study released or about to released that pegs MTBE as cancer-causing when exposed to it long-term, which means refineries will stop using it soon. I remember our Senator releasing a statement about it not too long ago.