Originally Posted by alkey
can you explain what styrene monomer is or does? is it normally shipped in pipe lines?
It's the root chemical in making polystyrene plastic one of several name brands being polyester. It's used to make foams, is a common resin in fiberglass and composite structures, solid, and is made into threads for cloth and ropes.
It is pumped through pipe lines with other hydrocarbon and alcohol based fluids. They use a water slug between different materials in the line, just in case you wonder how water gets into gasoline, this is a major source.
I'm not saying that is this resin but from the pictures it looks like a plastic that is falling out of solution with the fuel and curing onto surrounding surfaces. It looks pretty hard, is it hard, soft or gooey? If you have a fuel cell which someone else indicated you did it can be that certain solvents in the fuel are melting it and redepositing it. I guessing as I'm not there just looking at the pictures, but I've seen this kind of stuff before and a plastic resin was what it turned out to be.