Twenty-one people have been held accountable for a toxic suffocation incident in Lyuliang, Shanxi province, in February, according to recent investigation results from the provincial emergency management department.

The incident occurred on Feb 23 in the dust collection area of a coking plant belonging to Jiaokou Wangzhuang Pig Iron Co in Jiaokou County of Lyuliang, which killed four people and led to direct economic losses amounting to over 6.62 million yuan ($1 million).

The investigation showed that it was a production safety accident directly caused by several factors: two workers violated operational procedures, and on-site leading personnel conducted blind rescue attempts, leading two workers to suffocate during the rescue.

It also pointed out that the local government and relevant departments failed to enforce the company's responsibility for safety.

The 21 responsible people and units will receive various punishments according to the results of the investigation.

Criminal prosecution was recommended for three individuals, including the on-site worker, the pushing-car maintenance team leader and the manager of the coking plant.

Nine people, including the coke plant engineer and the safety officer, will have administrative penalties including fines. Disciplinary actions are also recommended for another nine people from government organs.

Guo Yanqi contributed to this story.