The Palumbo Spa chief, 63, was held with his son Raffaele,38, in April as Italian police investigated alleged illegal disposal of wastefrom their Messina yard.
A court hearing has been set for 19 December, with judgement expected in February 2014, according toreports in Malta, where Palumbo also has a shipyard.
The court in Sicily ruled the arrest was no longer necessary. His son was also released.
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