A total of 62 people have been held accountable for a January accident at a steel plant in North China's Inner Mongolia Autonomous Region that killed 10 people and injured 84 others, according to an investigation report published on Sunday, which also detailed the cause of the incident.

The explosion, originating from a 650-cubic-meter saturated water and steam spherical tank, took place at 3:03 pm on January 18.

The investigations found that the blast was caused by the long-term deterioration of a spherical pressure vessel used to store saturated water. Authorities said the No. 1 vessel had been subjected to prolonged corrosion, combined with localized stress and repeated loading during operation, causing irreversible damage to its inner wall through a combination of alkaline stress corrosion cracking and corrosion fatigue, according to the report issued by the Emergency Management Department of Inner Mongolia Autonomous Region on its official website.

The damage continued to accumulate until it penetrated the vessel wall, resulting in a leak of saturated water near the north side of the lower circumferential weld. Investigators said no effective emergency measures were taken after the leak was discovered.

About 90 minutes later, pressure inside the vessel exceeded the defective tank's structural limit, causing the circumferential weld to rupture rapidly around the entire vessel. The tank then disintegrated, triggering the instantaneous flash evaporation of a large volume of saturated water and a subsequent explosion on January 18.

Following the accident, the central and local governments have launched emergency response and mobilized search and rescue efforts. More than 1,300 rescuers and over 70 emergency and ambulance vehicles were deployed in the operation.

The investigation report identified major failures by the Baotou Steel Plate Plant, Inner Mongolia Baotou Steel Union Co Ltd and Baotou Iron and Steel (Group), as well as by companies involved in the project. It also cited shortcomings by regulatory authorities and local Party committees and governments.

According to the report, prosecutors in Kundulun district, Baotou, have approved the arrests of seven employees of the steel plate plant on suspicion of criminal offenses. Investigators also recommended that six other individuals involved in the accident be referred to judicial authorities for criminal investigation.

In addition, the report proposed administrative penalties, Party disciplinary measures and organizational sanctions against officials from Baogang United Steel and its affiliated companies, the companies linked to the accident, the Party committees, governments, market regulation and emergency management authorities in Baotou and Kundulun district, as well as officials from the regional market regulator, emergency management department and state-owned assets regulator.