A regional court ordered the release of Can Gürkan, the CEO of a mining company which runs a coal mine in western Turkey where 301 workers died on May 13, 2014.
Gürkan was among the five defendants of the staff of the company, Soma Kömür İşletmeleri, accused of manslaughter by deliberate negligence after miners died of smoke inhalation following a fire in the mine.
A lower court in Izmir, a city near the town of Soma in western Manisa province where the mine is located, had handed down prison terms ranging between 15 and 22 years for defendants last year.
Plaintiffs took the case to the higher regional court but the court upheld the verdict on Friday and ordered Gürkan's release with a ban of traveling abroad. Other defendants, including the mine's managers, will remain jailed.
Gürkan is the son of Alp Gürkan, the owner of Soma Holding, the parent company of Soma Kömür İşletmeleri, who was acquitted in the case earlier.
He and others were charged over allegations that they neglected worker safety in the mine after miners without enough equipment to protect them from smoke inhalation and without enough fire exits dropped dead in the worst mine disaster in Turkey's history.