Seven people face further investigation in connection with a fire that killed 23 people and injured eight others at a lithium battery plant in Hwaseong, Gyeonggi Province, in June.

The Gyeonggi District Employment and Labor Office turned over three of those cases to prosecutors on Friday, recommending charges under the Serious Accidents Punishment Act, the Occupational Safety and Health Act, and the Act on the Protection of Temporary Agency Workers.

It referred the other four cases to the police. 

The three people whose cases are in the hands of the prosecution are Park Soon-kwan, head of the battery manufacturer Aricell; his son Park Joong-eon, its head of factory management; and a temporary staffing agency executive identified only by the surname Jeong.

The police and labor authorities believe Aricell illegally dispatched untrained workers to the factory under a supply deadline, which resulted in a faulty battery that caused an explosion and a fire. The workers could not escape, allegedly because there was no evacuation route.