Yes, I guess official lead limits could be in parts-per-million of chemical amount instead of parts-per-million of weight (I don't think volume works) - do you know which? As you say, either way it's easy to tell which chalk might be dangerous.
pj
chgo
[EDIT: LOL, Renfro - I was typing this while you were posting the answer above. Thanks for finding out. Mr. Bond is right in principle.]
With the lead as high as it was in the green, I would just assume (and at least hope) that the green's formula has been changed since that time.
But I never thought to ask until now, so I shot an email over to Skip to see whats up with that.
Hopefully he'll tell me that the dead cats they were using for green coloring have been replaced by organically raised dead frogs.