Consumer Reports said on Wednesday it had found "concerning" levels of lead and cadmium in a third of various chocolate products it tested recently, and called on Hershey to reduce the amounts of heavy metals in its chocolate.
Why would any milk fat be required for something to be defined as chocolate? Chocolate doesn't have to contain any milk at all. The only thing my brief research turned up was this, stating that they could only contain up to 5% non cocoa vegetable fats.
Edit:
This claims there is a minimum milk fat for milk chocolate, but no requirement for chocolate in general.