Prosecutors on Wednesday sought a 20-year prison term for the chief executive of lithium battery maker Aricell over a deadly fire at the company's plant last year that claimed nearly two dozen lives.

The prosecution demanded the term for Aricell CEO Park Soon-kwan during a hearing at the Suwon District Court on charges of violating the Serious Accidents Punishment Act and the Occupational Safety and Health Act, among others.

The deadly blaze at the battery maker's plant in Hwaseong, just south of Seoul, in June last year, killed 23 workers, including 18 foreigners, and injured eight others.

The prosecution accused Park of failing to properly set up a safety management system despite his responsibilities as CEO.

"This was the worst casualty accident since the enforcement of the Serious Accidents Punishment Act, and most of the victims were illegal migrant workers vulnerable to safety management," the prosecution said. "This accident left migrant workers in a safety blind spot."

The prosecution also demanded a 15-year term for Park's son, a general manager of the company, on similar grounds.

Park's was detained last August, marking the first time the head of a company was formally arrested since the enforcement of the Serious Accidents Punishment Act in 2022. The law calls for punishing owners or CEOs of companies with at least one year in prison or fines of up to 1 billion won ($725,000) for industrial accidents.

Park was indicted under detention the next month but was later released on bail.