White build up on rack

[Danny]

Whats up all. Happy 4th. I got the itch to fix up my car again and noticed a white build up (corrosion maybe?) on the ps rack. Passenger side, near the fuel filter. It is similar to the build up that i see on my fuel lines. The rack was recently replaced and i dont recall seeing this stuff on the old one. Anyone know what this is from or the cause of it? Oxidation maybe, fuel leak? I have a pic of it, but it was to big to post here. If need be ill email it off list if a further description is necessary. TIA
 Danny