I have no experience with Zero Rust, but I have used POR-15 and can tell you first hand that getting it in your lungs sucks royally. I did a cab corner and thought "It's just a small job, I don't need to get my painting gear out". WRONG!!!
I was sick as a dog for the next 3 days. I'd say whatever you use wear the proper safety gear- at minimum a properly rated paint mask and safety glasses.


Bill Burmeister