Rome, January 2 - The Taranto prosecutor's office filed a challenge against the Italian government for its so-called "ILVA decree" in the Constitutional Court on Monday, according to court sources. The prosecutor's office of the southern Italian port city objects to recent government intervention on behalf of the deeply troubled ILVA steel plant - Italy's largest - whose emissions were ruled a toxic menace to public health by the Taranto court. The Taranto prosecutor's office claims that a decree passed by the Italian government, which defines conditions under which the steel plant can continue to operate, constitutes a conflict of powers between branches of the State. Italy's outgoing technical government passed a decree designed to countermand orders by the Taranto court, which would have effectively shuttered the plant and left thousands of workers off-the-job. Last July, the Taranto court ordered a shutdown of the plant's smelting areas. Months later, the court also sequestered manufactured parts awaiting shipment. ILVA appealed the court's seizure orders on the basis of the government's decree, which permits plant operation at partial capacity while ILVA undertakes well-defined clean-up measures. When the Taranto court rejected ILVA's appeal in late November, the company declared imminent total shutdown of the plant, sparking strikes and protest at its facilities in Taranto and near Genoa. Italian Environment Minister Corrado Clini introduced an amendment to the government decree designed to overturn the Taranto court ruling. The amended decree was overwhelmingly approved by parliament in December. The Council Chamber of the Constitutional Court must now decide whether the Taranto prosecutor's challenge is admissible. The Taranto prosecutor's office requested urgent review of the case, but the Constitutional Court is under no prescribed time-constraints to do so.