After reading some comments on the internet, I saw this: It contains MEK(methyl ethyl ketone) and it's a very aggressive chemical and used in plastics industries to melt and join 2 plastic parts together. It will ruin any rubber seals or plastics components in your gas tank or entire fuel system. If you ever have to use this one don't leave this stuff in your tank for an extended period of time. You can put some plastics or rubber seals in B12 and watch it. B12 must melt down some plastics and rubber seals and it went to combustion chamber and eventually it clogged up your catalytic converter. I don't know why a fuel additives using MEK in it. It's dangerous chemicals dude. I work with this MEK and I know what I'm talking about Will Berryman's B-12 Fuel Injection Cleaner harm any plastic parts in the fuel system on my 2011 Toyota Camry SE V-6