Phosphorous tends to burn like a mother****er and doesnt stop at clothes lines or even surface tissue. Willie Pete doesnt get dispersed like a spray...its spread like shrapnel. You cant tap it out or smother it. I'm not saying what that is nor am I saying what it isnt...but that certainly doesnt look like any WP burn damage on an individual I have ever seen...except perhaps if someone found a large chunk of it burning and took their shirt off and sat around it to get a tan.
I could be wrong......but I dont think so.