Five Turkish soldiers died after being exposed to ‘silent killer’ methane gas during a search operation in caves in northern Iraq on Sunday, the defense ministry said.

The incident comes at a sensitive time with Turkey in talks to end the conflict with the Kurds after the PKK militant group agreed to end its decades-long armed struggle.

The conflict, which began in 1984, has cost more than 40,000 lives.

The incident occurred as they were searching for the remains of a soldier who was shot dead by Kurdish fighters in the area in May 2022, whose body was never recovered, it said.

At the time, Turkey was waging Operation Claw Lock, with its troops seeking to eradicate Kurdish PKK militants holed up in caves along the border.

“During a search operation in a cave… previously known to have been used as a hospital… 19 of our personnel were exposed to methane gas,” it said.

They were immediately taken to the hospital for treatment, but five of them died, it said.

News of the deaths emerged as a delegation from the pro-Kurdish DEM party was visiting jailed PKK founder Abdullah Ocalan as part of the ongoing negotiations with the Turkish government.

“During the meeting, we were informed that there were soldiers who lost their lives due to methane gas poisoning in the territory of the Kurdistan Regional Government,” the delegation said.

“This incident caused Mr Ocalan and all of us deep sadness. We wish Allah’s mercy to those who lost their lives and offer our condolences to their families and relatives.”

Methane gas, a colorless, odorless, and highly flammable substance, can pose a significant hazard in places such as caves. Naturally occurring in environments where organic material decays, methane can accumulate in poorly ventilated underground areas, creating treacherous conditions.

Its dangers stem from two primary risks: asphyxiation and explosion.

Methane displaces oxygen in the air, and in high concentrations, it can lead to suffocation by depriving the body of oxygen. Additionally, methane is highly flammable, and even a small spark can trigger a deadly explosion.

In caves, methane can go undetected without proper monitoring equipment due to its lack of smell or visible presence. Symptoms of exposure, such as dizziness, nausea, and shortness of breath, may not be immediately noticeable, especially in low-oxygen environments where fatigue is already common.

This makes it particularly hazardous for explorers, miners, or soldiers operating in such confined spaces without adequate precautions, such as gas detectors or ventilation systems.

The risks of methane in caves can be mitigated through the use of gas detectors, which are crucial for detecting dangerous concentrations. Training personnel to recognize the signs of methane exposure and equipping them with protective gear, such as oxygen masks, can also save lives.

The incident in Northern Iraq serves as a warning of the importance of these precautions, particularly in military operations where caves may be strategically significant but inherently perilous.