Censor.NET reports citing local news outlet 061.ua.
Three people were killed by the explosion on the spot. One more person in grave condition was taken away by the ambulance. He died en route to the hospital. The police, prosecutors, rescuers, and doctors are working at the scene.
The police reported that the deceased persons were not the plant employees but contractors who performed welding works.
The cause of the incident is not yet known. The case will be investigated by the State Service of Mining Supervision and Industrial Safety.
Sources of Ukrinform news agency also confirmed this information: "Three people were killed by a blast that caused no subsequent fire. One person is in a grave condition in intensive care unit. All the emergency services left for the scene."
Zaporizhkoks CJSC, a subsidiary of Metinvest Group, is one of the largest coke producers for the domestic metal industry and one of Ukraine's largest exporters of chemicals. The enterprise produces about 10 percent of all domestic coke.