This blog post examines corporate ethics issues and the flaws in the hazard assessment system, focusing on the Oxy humidifier disinfectant incident.
The Oxy humidifier disinfectant incident is the worst disaster in South Korean history, resulting in 239 deaths and 1,528 cases of lung disease. The specific causative agents in the disinfectant were PHMG and PHG, toxic substances classified as pesticide ingredients in the United States. The shocking fact is that these toxic substances circulated in the market for a staggering 17 years until 2011, when the Korea Disease Control and Prevention Agency (KDCA) recognized the situation and launched an investigation. Not only the victims but also citizens who did not use the product were outraged, leading to a boycott of the company’s products. Even more shocking was the realization that Oxy’s products, uncovered during this process, were everyday items readily available in our lives. We had been living unaware of the toxic substances right beside us.
So, should citizens live relying on corporate conscience regarding the presence of toxic substances? Of course not. Under current law, toxic substances undergo numerous testing stages before being sold commercially. This entire testing process is called a risk assessment. Only products with a risk level below a certain threshold can be sold after passing this risk assessment. PHMG and PHG were substances already designated as toxic in the United States and should have undergone a risk assessment for use in disinfectants. Many citizens who learned about the Oxy incident criticized the retailers, asking how toxic substances could be sold without a risk assessment. The shocking truth is that these toxic substances did undergo a risk assessment, and the conclusion was that they posed ‘no risk’.
To understand the Oxy incident more deeply, it is necessary to know the stages involved in a risk assessment. Before that, it is essential to clarify the terms ‘harmful’ and ‘risk’, as used in toxicology. This is because even a minor difference of one character can significantly alter the meaning.
‘Excessive heavy metal accumulation poses a risk’ and ‘Excessive heavy metal accumulation is hazardous’ are clearly different statements. Everyone knows that ‘risk’ and ‘hazard’ are toxicological terms denoting danger. To distinguish between risk and hazard, let’s first examine their dictionary definitions. Hazard refers to the inherent risk of a chemical substance, such as its toxicity, that can adversely affect human health or the environment. Risk refers to the danger associated with the potential exposure to a hazardous substance.
Just the dictionary definitions might not fully convey the difference between the two terms. Hazard is a term that describes the degree of danger the substance itself poses, while risk describes the degree of danger when the substance’s hazard is exposed to humans. Hazard is influenced by both the intrinsic toxicity of the substance itself and factors related to the exposure of people using the substance. Factors related to the latter include the likelihood of exposure, duration of exposure, frequency of exposure, and intensity of exposure. This is precisely why, from a human perspective, the hazard of a substance serves as the basis for assessing risk. No matter how high the intrinsic toxicity of a substance, if there is no lifetime exposure, it will not harm humans. This is why toxicity assessment for humans is called hazard assessment, not toxicity assessment.
Hazard assessment consists of four main steps: hazard identification, dose-response assessment, exposure assessment, and hazard determination. Hazard identification means identifying the types of diseases and health disorders that can occur. There are several methods for classifying toxicity levels, but the most representative is acute toxicity assessment. This is categorized using a toxicity indicator called LD50, which relatively indicates the magnitude of toxicity. LD50 signifies the dose that causes 50% of the test animals to die when administered. Through acute toxicity assessment, toxicity levels are divided into six grades, ranging from ‘practically non-toxic’ to ‘hypertoxic’.
Dose-response evaluation involves determining the relationship between exposure levels of a hazardous substance and toxic responses through animal clinical trials. Substances with no threshold, causing harm even at low doses, are classified as carcinogens. Substances with a threshold, exhibiting toxicity only at doses above that threshold, are classified as non-carcinogens. The method for calculating reference exposure levels differs depending on whether the substance is a non-carcinogen or a carcinogen. The third step, exposure assessment, involves estimating the actual amount of harmful substances to which humans are exposed. It considers all influencing factors: the release area, release quantity, release timing, and the substance’s inherent properties such as mobility, degradability, and human exposure pathways. Subsequently, exposure factors are determined, with information on lifespan, body weight, and average exposure duration quantified and presented. This enables the final calculation of the chemical intake.
Thus, hazard assessment is a highly systematic evaluation procedure. However, the Oxy incident had problems starting from the very first step of the hazard assessment process: hazard identification. During the hazard identification stage, SK Chemicals intentionally mislabeled the toxicity to conceal the hazard. Furthermore, in the Material Safety Data Sheet (MSDS) prepared by SK Chemicals on March 6, 1997, PHMB was stated to be a hazardous substance under the Industrial Safety and Health Act and to have severe eye and mucous membrane irritation. However, in a patent application filed by SK the very next day, on the 7th, it was stated that PHMB was not regulated under the Industrial Safety and Health Act and had low eye and mucous membrane irritation. In other words, the toxicity was also falsely labeled in the patent.
Problems were also found in the second stage: the dose-response assessment. In this stage, involving animal clinical trials, the results of an inhalation toxicity test on 15 experimental mice were manipulated. Professor Cho Mo of Seoul National University, a leading authority in toxicology, conducted the risk assessment by analyzing only the data from the two surviving mice in the inhalation toxicity test, having received financial compensation.
No matter how systematic the hazard assessment method, it is human responsibility to ensure this system functions properly. Nearly all problems concerning toxic substances arise not from flaws in hazard assessment itself, but from humans failing to adhere to it. The price paid for ignoring legally mandated hazard assessments to secure personal gain was enormous. Hazard assessment is even more critical because it directly concerns life. Particularly with toxic substances, their effects often don’t appear immediately but accumulate within the body. Since harm isn’t immediately apparent, the cause of illness remains unclear, leading to prolonged exposure. For victims, proving that harm resulted from a specific product becomes difficult. Even if compensation is received after proving harm, what remains is a body already damaged by toxicity.
Even now, citizens live in fear that products on the market may be distributed while concealing their hazards. Ultimately, the safety of the entire population cannot be entrusted solely to human conscience and ethics. Institutional mechanisms capable of controlling human greed and corporations are essential for the hazard assessment system to function properly. Experts in hazard assessment must clearly define their professional ethics, and every individual within a company must clearly define their occupational ethics. One alternative is to disclose all experimental data related to the risk assessment process. This disclosure ensures transparency in the evaluation and guarantees its reliability. The introduction of institutional mechanisms is urgently needed for the proper functioning of the risk assessment system.
