[Kim Byung-min's Science Village] The Era of Sterilization Brought by COVID-19... What If the Second Humidifier Incident Occurs?

The Two Faces of Chemical Substances

Byungmin Kim, Science Writer

Recently, there was an accident where a five-year-old child pressed the cap of a hand sanitizer, causing the sanitizer to spray into their eye. Although the child was rushed to the emergency room, unfortunately, the cornea had already been burned. The sanitizer was placed too high for the child. It was a detail that adults had overlooked. From an adult’s eye level, it seemed perfectly natural to place it at that height, so no one even questioned it.

We live in an era where questioning has been lost. In the face of growth and efficiency, questions might seem cumbersome. But what is even more unfortunate is when questions receive not only difficult answers but no response at all. At such times, one feels like a frustrated parent of a teenager going through a turbulent phase.

There is a German term called ‘Wagenburg mental.’ Wagenburg means a fortress made of four-wheeled carts. These carts served as a kind of mobile fortress, mainly used as a military tactic. In the 15th century, when the allied forces of Hungary, Poland, and Wallachia clashed with the Ottoman army, they reportedly used the Wagenburg tactic to block the Ottoman offensive.

Thus, the term is used metaphorically to describe a mental state where no one accepts outside opinions, ignoring even sounds from outside and isolating oneself mentally. But what if the very party that should respond shows this attitude? What if that party is a nation?

First Trial of the Humidifier Disinfectant Case
Not Guilty Verdict for Distribution and Sales Companies
Only Victims, No One Held Responsible

Recently, the first trial of the humidifier disinfectant case was held. The court acquitted the distribution and sales companies involved in the case, citing a lack of evidence to prove a causal relationship between the disinfectant’s ingredients and lung disease. It became a case with victims but no one held accountable.

Let’s revisit the humidifier case. There were four problematic substances included in the humidifier disinfectants: Polyhexamethylene Guanidine (PHMG), Ethoxyethylguanidine Chloride (PGH), Chloromethylisothiazolinone (CMIT), and Methylisothiazolinone (MIT). The reason for bringing up these difficult chemical names is not to explain their chemical properties or differences.

These substances differed not only in their physical properties but also in manufacturers, sellers, and product release periods. The earliest substances were CMIT and MIT, whose causal relationship with pulmonary fibrosis had not yet been established. Even in 1994, when products containing these substances were released, the ‘Toxic Substances Control Act’ existed. However, the law included a clause exempting chemicals used before 1991 from toxicity review. As a result, these two substances slipped through regulatory gaps. Even if a chemical had been used previously, if its use changed to a new application like humidifiers, someone should have intervened to check for unverified toxicity.

Then, in 1996, PHMG appeared. This was a new chemical substance not seen before. As a new chemical, it underwent toxicity review but passed without submitting toxicity test data. How was this possible? PHMG is a polymer. Most substances starting with ‘poly-’ are polymers. The regulations for toxic substance reporting allowed polymer substances to omit submission of test reports. Subsequently, in 2003, PGH also passed the review without resistance, allowing all four substances to enter the market.

It is true that polymer substances are relatively safer than low molecular weight substances because their large molecular weight prevents them from entering cells easily or reacting with tissues. However, PHMG and PGH are ‘cationic polymers.’ Having ionic properties means they are electrically polar, which implies they have the potential to react chemically.

Experts likely knew that such polymer substances could exhibit toxicity when dissolved in water. By that time, advanced countries were already aware of cationic polymer substances. However, the regulations made toxicity review of cationic polymers optional, not mandatory. From a company’s perspective, there was no reason to undergo the review.

In fact, there were countless opportunities over nearly 20 years to prevent this disaster. Many stakeholders were involved with chemical substances. Despite many eyes watching, no one asked the simplest question: ‘Is this substance safe?’

1957 German Sedative ‘Contergan’
10,000 Newborns Born with Deformities
German Government Took No Action

In 1957, the German pharmaceutical company Gr?nenthal produced a sedative called ‘Contergan,’ which caused one of the most tragic pharmaceutical accidents. Up to 10,000 newborns in Germany were born with deformities, and many fetuses did not survive. However, the German government had no information about the drug’s main ingredient, ‘thalidomide.’ Although there were voices suspecting Contergan, the government took no action and instead claimed the cause was something else.

Even after it was revealed that thalidomide was the cause of the tragedy, the German government did not take special measures. The Federal Health Office, the responsible agency, avoided accountability. The pharmaceutical company also failed to properly control the situation, worsening the problem. This attitude of German institutions at the time exemplifies the ‘Wagenburg mental.’

But this attitude is not unfamiliar to us. The early response of our government to the humidifier disinfectant damage and the current situation are not very different.

Today, humanity is fighting a virus never experienced before. Alcohol, once used only for wound disinfection, has become a daily essential. We disinfect our hands and surrounding spaces whenever we move from one place to another. Sanitizers have become everyday necessities. However, at some point, disinfectants began to be sprayed on our bodies. Spaces where one must pass through mist-like disinfectants sprayed from both sides of entrances, like metal detectors at airports, are increasing. Fogging or spraying disinfection is now routinely carried out in multi-use facilities.

But the substances used for disinfection are not limited to alcohol. While there are various substances, commonly used ones include ammonium compounds such as ‘hypochlorous acid’ and ‘benzalkonium chloride.’ Chemical names are always difficult and unpleasant to hear. Simply put, both ingredients are known to have potential inhalation toxicity.

For Humanity That Has Experienced Painful Past,
‘Is This Substance Really Safe?’
A Question Essential in Our Time

We must frame this situation as a question: ‘Is it really safe to spray substances with inhalation toxicity into the air?’ ‘Isn’t this a scenario like the humidifier disinfectant case?’ We need to retrieve and piece together the fading fragments of past incidents and compare them with the scenes unfolding before our eyes now. If we failed to do this then, we must do it now. This is the lesson learned from painful past experiences.

Of course, chemical substances perform many functions in large quantities. If exposure is occasional and brief, there may be no need for alarm. But some people must pass through that mist daily, and some even make spraying their occupation.

In the past, alchemists could control power through substances. They gave power to some and took it away from others. Sometimes, they handed power to the foolish, causing humanity to pay a harsh price. For this reason, alchemists had implicit rules. They bore ethical responsibility for handling substances. They were always strict with themselves, constantly reflecting and ensuring they did not harm others physically or emotionally. Some interpreted alchemists’ practice of encrypting research processes and results as academic selfishness. But there was a profound reason: dangerous knowledge should not be handled carelessly. Can we find the ethics and justice of alchemists in modern times?

Again, we ask: Is this substance safe? Someone must come out of the Wagenburg and answer. And in the process of answering, eye level is important. Especially in science, it must be valued even more. Science speaks a different language. The language of science, with its difficult math, formulas, units, and terminology, is like a foreign language to ordinary people. Therefore, answers must be given in a way that the other party can understand, almost like interpretation. The party to be answered must receive answers at their own eye level.

Adjunct Professor, Nano Convergence School, Hallym University