Last week's acquittals of 13 corporate executives in a deadly humidifier sterilizer case were caused by the court's wrong interpretation of the causal relations between chemicals contained in sterilizer products and victims' lung-related illnesses, a group of scholars argued Tuesday.

The Seoul Central District Court ruled last Tuesday that Hong Ji-ho, former CEO of SK Chemical; Ahn Yong-chan, former CEO of Aekyung Industrial; and 11 other corporate executives are not guilty of professional negligence resulting in death, triggering strong protests from families of victims and civic activists.

The defendants were accused of manufacturing and selling Humidifier Mate, a humidifier sterilizer that includes harmful chemicals, in the early 2000s.

A number of environmental and health researchers and lawyers denounced the ruling in a news conference in Seoul on Tuesday, saying the judges in the case may have misunderstood the scientific causal relations between humidifier disinfectants and respiratory diseases that have so far resulted in the deaths of more than 1,500 victims.

Park Dong-wook, a professor of Korea National Open University, argued that the court may have turned a blind eye to the causal link between humidifier disinfectants and lung diseases by saying that victims had underlying diseases.

"It is impossible to explain the reason why children aged 3 or 4 got lung diseases, which usually affect aged people. Nevertheless, the personal causal relationship was completely ignored by the court," Park said.

Referring to the court's refusal to recognize a link between lung-related illnesses and key ingredients of humidifier cleaners, such as methylchloroisothiazolinone (CMIT) and methylisothiazolinone (MIT), the professor said that animal testing is an option and that there are many toxins not found in animal testing, such as thalidomide and DDT.

Prior convictions in similar cases were related to chemical products containing other substances, such as polyhexamethylene guanidine (PHMG).

The Korean Society of Environmental Health also issued a statement saying the subject of the court trial has been wrongfully changed from the defendants' fault to the limits of science in proving a link between CMIT and MIT and diseases.

"The causal relationship has to be proven in criminal cases, but the subject should not be the health damage that science should clarify but the intentions and actions of the defendants," the statement said.

Park Tae-hyun, a professor at Kangwon National University's Graduate School of Law, said that last week's acquittals of corporate executives were an unprecedented court ruling relying on science.

"There is an inevitable limit in science's pursuit of truth. If zero defects alone are recognized as truth, most of the facts cannot be admitted," said Park, urging the appellate court to lower the criteria for proof in consideration of the difficulty in proving the causal relationship between substances and damages.

The humidifier disinfectant scandal is one of the country's worst consumer goods disasters.

In 2011, consumers started to report deaths and illnesses allegedly tied to humidifier disinfectants, widely used in households in dry winters. A government-led investigation confirmed the link between the two in February the next year.

According to the ministry, a total of 7,103 damage cases, including more than 1,500 deaths, have been reported as of the end of last year. Among them, 4,114 cases have been confirmed to be related to toxic humidifier disinfectants.

Shin Hyun-woo, former chief of Oxy Reckitt Benckiser Korea, was sentenced to seven years in prison in 2017 for causing homicide through professional negligence and falsely advertising the company's disinfectant as safe.

In August 2019, Ko Kwang-hyun, another former CEO of Aekyung Industrial, was sentenced to 2 1/2 years in prison for covering up toxicity-related data on the company's disinfectant product. (Yonhap)