Some 787 people were inside the mine at the time of the accident.
ISTANBUL — Hopes were fading, officials said, as rescuers raced Wednesday to reach more than 200 miners trapped deep underground in a coal mine in western Turkey following an explosion and fire that may be one of the worst mining disasters in the nation's history.
Energy Minister Taner Yildiz said 787 people were inside the coal mine in Soma, about 155 miles south of Istanbul, at the time of the explosion on Tuesday. Some 232 were confirmed killed and 363 had been rescued but the death toll is expected to rise.
"Regarding the rescue operation, I can say that our hopes are diminishing," Yildiz said. He said 57 mine workers were injured and that most of the deaths were from carbon monoxide poisoning after a fire was triggered by an electrical fault. He said the fire was still blazing inside the mine, hours after the blast.
EARLIER STORY: 166 dead, many trapped in Turkish coal mine
The blast happened during a change in shifts. Some of the survivors had initially retreated deeper into the mine, complicating the efforts of rescuers to reach them and to pump oxygen into the mine.
Mining accidents are common in Turkey, where safety conditions are sometimes poor. In 1992, a gas explosion killed 263 mine workers near the Black Sea port of Zonguldak.
SOMA Komur Isletmeleri A.S., which owns the mine, confirmed that a number of its workers were killed but would not give a specific figure. The company said the accident occurred despite the "highest safety measures and constant controls" and that an investigation was being launched.
"Our main priority is to get our workers out so that they may be reunited with their loved ones," the company said in a statement.
Andrew Watson, of Mines Rescue Service, a health and safety training company based in the U.K., said that the disaster unfolding in Turkey was different to the one in Chile in 2010 when 33 miners were trapped 2,300 feet underground for two months.
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"There isn't really a comparison to Chile because that was a hard rock mine whereas this is a coal mine. In a hard rock environment the mine creates the problem by what is brought in there. With coal, it's nature that supplies the problem. You get coal dust, methane and issues of spontaneous combustion," said Watson.
"The one thing we can say is that for decades now the means of controlling that environment in terms of the technology has been available," added Watson. "When the methane reached a certain point, the power should have automatically cut off. So that was either not in place here or it has not been managed properly."
Analysts said the safety standards in the mine were low.
"Turkish coal isn't very high quality — it is a brown coal variant called lignite — and thus, doesn't generate much value," said Hamid Akin Unver, an assistant professor of international relations at Kadir Has University in Istanbul. Unver said the Soma mining facility's operating company may have adopted low standards of safety.
The Turkish government, which has been rocked by recent allegations of corruption and mass protests, is likely to take another hit over the accident: In late April, lawmakers of the ruling party blocked an opposition motion for a parliamentary investigation into the safety of the Soma mine, saying it was safe.
According to a report in Turkish daily Hurriyet, the private company that operates the mine had recently drastically cut production costs from $130 a ton to $24 a ton by using domestically produced electric transformers and non-unionized subcontractors.
Turkey's Labor and Social Security Ministry said in a statement that the mine had undergone five inspections since 2012, the last one in March 2014, and no problems had been reported.
Turkish social media was abuzz Wednesday with renewed calls for protests in Istanbul and other large cities. Many believe that corruption played a role in the disaster.
"Under every stone you lift, you find government corruption," said Aise Karakaya, who was preparing to attend a demonstration near Taksim Square in Istanbul on Wednesday afternoon. "I am sick of this. I don't care if police attack us again to protect the murderers."
Throughout Tuesday night in Soma, people cheered and applauded as some trapped workers emerged, their faces and hard-hats covered in soot. Dozens of ambulances drove back and forth to carry the rising number of bodies as well as injured workers.
Emine Gulsen, part of a group of women who sat wailing near the entrance to the mine, chanted in song, "My son is gone, my Mehmet." Her son, Mehmet Gulsen, 31, has been working in the mine for five years.
Mehmet Gulsen's aunt, Makbule Dag, held out hope. "Inshallah" (God willing), she said.
Contributing: USA TODAY's William Welch from Los Angeles and Kim Hjelmgaard from London; Associated Press