Puglia regional governor Nichi Vendola and 43 other people as well as three companies were ordered to stand trial in October for causing an environmental disaster at the scandal-hit Ilva steelworks in Taranto.
Vendola is accused of abuse of office for allegedly pressuring the head of regional environmental protection agency Arpa, Giorgio Assennato to tone down reports on the toxic effects of emissions from the Ilva plant.
Italy's prime minister Matteo Renzi won backing in parliament on Thursday to keep open the troubled plant against the will of local magistrates in southern Italy who say it is unsafe.
The government took control of Ilva in January to save some 16,000 jobs after magistrates ordered the steelworks to be closed several times amid accusations that toxic emissions were causing high cancer rates among Taranto residents.
The government is now helping fund a clean-up to save jobs at the steelworks. The plant is the city's largest employer and has Europe's largest output capacity at 11 million tonnes.
Since it was placed under special administration in 2013 it is producing far under capacity and is losing tens of millions of euros a month.
Puglia's former regional councillor for the environment Lorenzo Nicastro was acquitted Thursday in a fast-track trial of covering up for Vendola's alleged intimidation of Assennato.
A policeman and a lawyer were also cleared in the fast-track trial while a priest was jailed for 10 months and an advisor to Taranto prosecutors was sentenced to three years and four months in prison.
The three companies ordered to stand trial on 20 October are Ilva, owned by the Riva family, its holding company Riva Fire and another Riva company.
