ROME (AP) — Premier Matteo Renzi added his voice to a chorus of outrage across Italy on Thursday after the country's highest court threw out a conviction against a Swiss businessman for some 3,000 asbestos-related deaths blamed on contamination from a construction company.

The Court of Cassation ruled late Wednesday that the statute of limitations had expired in the environmental negligence case against Stephan Schmidheiny, a former executive and key shareholder in the Swiss construction firm Eternit.

An appeals court in 2013 upheld the conviction and increased to 18 years from 16 the prison term handed down by a lower court in 2012.

Renzi said Thursday that the case showed how Italy's justice system must be reformed to speed up trials.

"It's not possible that for some cases the demand for justice runs out because there are some wounds that don't know time limits," he said.

Amid an outcry from relatives of the victims, politicians and environmental groups, the high court took the unusual step of defending its decision Thursday before its written motivations are released in three months' time.

In a statement, the Cassation said the charge in question was that of environmental disaster — not manslaughter — and that it therefore couldn't ignore the expiration of the statute of limitations, which started ticking in 1986 when Eternit closed its four Italian plants.

The statement appeared to be a reference to a new investigation opened by Prosecutor Raffaele Guarinello alleging manslaughter. Guarinello was quoted by Italian media as urging relatives of the victims to not lose faith in Italian justice.

A spokesman for Schmidheiny was quoted as urging the Italian government to "protect" him from any more "unjustified" charges, noting that Schmidheiny never had an operative role in the company and never received any profit from his shares in it.