Van der Waals radii used in EDTSurf

I have used EDTSurf which works nicely for constructing molecular surfaces. However, I was wondering if someone can help me with one thing: I need to know the Van-der Waals radii that are used for the different atoms. I suspect they are defined in CommonPara., I found the following code which very likely defines the VDW radii:

static double rasrad[ ]={1.90,1.88,1.63,1.48,1.78,1.2,1.87,1.96,1.63,0.74,1.8, 1.48, 1.2};//liang
// ca c n o s h p cb ne fe other ox hx

However, I'm not 100% sure about the meaning, I guess Ca would be 1.9A, carbon 1.88 and so on, but what's the meaning of cb, ox and hx? Furthermore, Iron would have 0.74A when I look at the code snippet, which can't be right.

Regards, Christof