This report identifies the divers as snorkelers and identifies the location as root trail. -
Snorkeler run over by boat and loses arm off Palm Beach Root Trail is a road on Palm Beach Island that is roughly 2 miles south of Lake Worth Inlet & just north of the Flagler bridge on the ICW. This is in conflict with the earlier report that the location was at the north end of Palm Beach Island
This report also references Root Trail -
Diver Loses Arm After Boat Accident in Palm Beach County
Someone who posted a comment below the following you tube video link claims to have been on site 15 minutes after the diver was taken by EMTs. The persons states that a pile of dive gear including a flag was on the beach at that time.