Aekyung Industrial Co. and SK Chemical Co. had allegedly manufactured and sold humidifier cleansers using the chemicals -- chloro-methylisothiazolinone and methylisothiazolinone -- between 2002 and 2011

The FTC had accused the two companies of not indicating the health risks of such chemicals on their products as the humidifier disinfectant case, one of the worst scandals involving a consumer product using poisonous chemicals, made headlines in South Korea.

But the watchdog closed the case, citing that Aekyung and SK Chemical are not liable to write the possible health hazards on the products as not enough evidence exists to say for certain that the chemicals are fatal.

However, the FTC set up a task force to reexamine the case as the country's environment ministry said the chemicals used as disinfectants are indeed hazardous to human health.

In its earlier examination, the FTC filed charges of false advertising against Oxy Reckitt Benckiser, the South Korean unit of the British company Reckitt Benckiser Group PLC.

The company had sold home humidifier sterilizers using other chemicals, such as polyhexamethylene guanidine known for causing death when people inhale it, without making proper warnings.

The South Korean prosecution has launched an investigation into the company as more than 100 deaths here have reportedly been connected to Oxy's humidifier disinfectants. (Yonhap)