A total of 164 companies including some of the nation’s largest electronics, chemicals, automotive and food makers were found to have dumped waste water tainted with toxic materials, the Environmental Ministry said Wednesday.

The ministry unveiled the result of its two-month investigation of 318 companies that discharge 2,000 tons of water per day.

The probe found that waste water from nearly half of them contained harmful chemicals, including phenolphthalein, copper, cadmium, chloroform, cyan and benzene, above permissible levels.

They include Ssangyong Motor, Dongsuh Food, Harim, Taekwang Industrial, CJ Cheil Jedang, Lotte Chilsung Beverage, Hyundai Oilbank, Hansol Paper, Lotte Chemical, Hanhwa Chemical, SK Hynix, Hyundai Steel, OCI, Kia Motors, Samsung Electronics and LG Chem.

Of them, the 72 most serious violators were referred to the prosecution, fined, ordered to close the facilities or halt their operations, according to the ministry.

By Kim Young-won (wone0102@heraldcorp.com)