Lo Presti is accused of violating norms for workers' safety after at least 150 workers at the airport complained of breathing and skin-related problems in the days following the fire, Ansa reported.
The probe comes as five air conditioning maintenance workers are being investigated over the blaze, which ripped through Terminal 3 at the airport in the early hours of the morning of May 7th.
The workers, who are employed by a company in charge of the maintenance of the airport's air conditioning units, were seen on CCTV working in the room where the fire broke out in the days leading up to the fire.
They had been installing an air conditioning unit in the room in order to stop an electrical panel from overheating. However, the unit turned off because it was not connected to an external power source. They are being investigated for suspected arson.
The director of the local ASL health agency and a manager at ADR are also being probed for endangering the health of workers after dangerous chemicals were detected at the site.
Hundreds of flights were cancelled as a result of the blaze and thousands of passengers had their travel plans wrecked.
The fire devastated the terminal's shopping area, which is home to a string of upmarket boutiques.
The terminal, which is one of four at the airport, serves flights to European countries outside the Schengen no-borders zone and destinations further afield with the exception of Israel and the United States.