ISTANBUL (Reuters) - A Turkish court sentenced five mining executives to up to 22 years in jail on Wednesday for their role in the coal mine disaster in May 2014 that killed 301 people, the ruling showed.

FILE PHOTO - A mining helmet and carnations are seen placed on the ground by demonstrators during a candlelight vigil for the victims of the Soma mining disaster in western Turkey, in Istanbul May 18, 2014. REUTERS/Yagiz Karahan

The deaths were caused by a fire that swept through the mine in the town of Soma, 480 km (300 miles) south of Istanbul. It was Turkey’s worst industrial disaster and the world’s biggest mining disaster this century.

Critics said the accident, which triggered mass protests, showed the government was too close to industry bosses and was insensitive, after Tayyip Erdogan, who was prime minister at the time and is now president, said the disaster was part of the profession’s “destiny.”

Mine operator Soma Holding denied negligence, while the government said existing mining safety regulations were sound.

Soma Holding’s general manager and technical manager were jailed for 22 years in prison, according to the ruling seen by Reuters. Two other company officials were jailed for nearly 19 years and the chairman was sentenced to 15 years in prison.

The court sentenced nine other employees to shorter jail terms and acquitted 37 of the 51 defendants who had faced charges ranging from “killing with probable intent” to “criminally negligent manslaughter”.

The deaths were caused by carbon monoxide spread through the mine by the fire.

Workplace accidents have become more common in Turkey, where rapid growth in the past decade has seen a construction boom and a scramble to meet soaring energy and commodities demand. Critics say worker safety standards have not kept pace.

Turkey has a poor mining safety record, particularly its in its coal mines. Hundreds of miners are killed by accidents in the industry each year.

The government tightened work safety rule and imposed tougher penalties for breaches in 2014, six months after the Soma disaster. New measures include financial penalties and prison terms for those found liable in fatal accidents.