Rust Problem.

[DMCVegas@xxxx]

In January I had my entire clutch system replaced. One component was 
a defective clutch master cylinder that leaked DOT-4 onto my chassis. 
About 3 months ago I was driving home from a friend's house one 
evening when the pavement on the higway turned white for almost a 
mile. When I got home the 11 o'clock news had a story on that there 
had been a hazardous waste spill on the highway. Something about a 
truck had spilled some sort of zinc-oxide waste from a local 
powerplant. Sure enough when I went out into the garage I had the 
white/gray-ish gunk still sticking to the bottom of my car. At the 
time I did the best I could to wipe the stuff off. 

Fast forward to last week.

My speedometer stopped working due to a worn speedo cup. When I 
removed the tire to replace the cup, I noticed a fairly good blanket 
of rust covering the chassis that had been exposed. It's only rained 
once here in the time since, but my car wasn't out in the storm. So 
my questions are these:

1. Where else should I start looking for rust? (when I get the 
chance, I'll probably remove the access panel to the gas tank to have 
a look around there).

2. How difficult is it to work with POR-15? (are there any tips out 
there that any one can give me?)

3. What exactly is this zinc stuff? I know that the DML is host to 
many owners that come from all professions, so I didn't know if 
someone out there might know not only what this stuff is, but what it 
can do. Since it was considered hazardous, could the epoxy 
undercoating be compromised (called the news station, and they were 
no help).

Thanks in advance!

-Robert
vin 6585