Prosecutors said Friday a local humidifier sterilizer maker used a high-health risk substance with its concentration rate 160 times higher than the level deemed harmless to the human body.

The Seoul Central District Prosecutors' Office said Cefu's chief, identified only by his surname Oh, used PGH, which was imported from a Danish company by his business partner as bactericides for computer devices, from 2008 onwards.

Oh did not have much knowledge about chemicals, according to prosecutors.

Cefu's humidifier sterilizer resulted in 14 deaths and 13 illnesses.

"There would not have been any problem if it was watered down enough, but as he did not have any expertise in chemicals, the concentration was too high," a prosecutor said.

From 2010, the company also used PHMG, toxic chemical also used by the British consumer goods manufacturer Oxy Reckitt Benckiser, until local authorities prohibited the sales of the products in 2011.

Some say government officials who did not properly control the import and distribution of toxic chemicals are also responsible.

Prosecutors, however, said they did not have evidence to hold them accountable at present.

The humidifier disinfectant case, one of the worst scandals involving a consumer product using chemicals, came to light after four pregnant women died of lung problems from unknown causes in 2011. A government-led investigation confirmed a connection between people who died of lung problems and the chemicals used to clean household humidifiers.

South Korea confirmed 221 people as victims. Among them, 177 had used Oxy products. Out of 90 deaths, 70 are believed to have been caused by the Oxy products. (Yonhap)