Wes,
Yes, during this shot my 15mm f2.8 fisheye was polluted with racegas.
It's hard to explain but they were kinda jumping over my noggin. Riley was leaking fuel out of the vent tube. They run high octane fuel which is somewhat corrosive.... apparently. I got home and the lens looked like an oilslick. I cleaned it for 30mins only to discover 1/4 circle had been burned in the outside section of glass. Its pretty much ruined. At any rate I dont recommend wide angle stuff at that distance. Even though i know these guys and trust them to no end... something weird always happens.
I really cant emphasize how hard mx is on your equipment. I went through 2 Canon 20d's in less than 6mos. If i had a nickle for every "error 99" received i could've bought a 3rd one. However it's why i upgraded to a MK II a few years back. The recent rains should help keep dust to a minimum for awhile. Just wear shoes you never want to see again, lol.