• Journal of Environmental Health Sciences
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• v.46 no.2
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• pp.128-135
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• 2020

Objective: The objectives of this study are to report the number of humidifier disinfectant (HD) associated health problems, including HD associated lung injury (HDLI), by year. This data was analyzed by the type of HD and HD brand. Methods: A total of 530 patients registered with the national program on HD through its third round were distributed based on the year when they developed their first health problem including HDLI (N=221). The distribution of health problems at diagnosis was clinically evaluated in order to examine the association between their lung injury and the use of HD. Results: The number of HD associated victims and HDLI patients was found to rise sharply from 2008 to 2011, with a peak in 2011. This trend was found not only for HD brands containing polyhexamethylene guanidine phosphate (PHMG), but also chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT). The number of patients who responded as developing health problems in the specific year was 35 for 2008, 51 for 2009, 108 for 2010 and 182 for 2011. Other types of HD brands and HD chemicals did not follow the trend of abrupt increase in HD associated patients since 2008. Conclusion: This study found the number of HD associated victims and HDLI patients who used HD brands containing PHMG sharply increased starting in 2008. A significant change in the process of manufacturing PHMG can be suspected with the abrupt rise in HD associated patients in specific years.

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.14.1-14.4
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• 2016

A total of 221 patients were evaluated to be humidifier disinfectant associated with lung injury (HDLI) through two rounds of programs through April 2015. The humidifier disinfectant (HD) brands most often associated with HDLI were found to be Oxy (n=151, 68 %) and Cefu (n=26, 17 %). Polyhexamethylene guanidine used for disinfectant for four types of HD brands including Oxy was found to be associated with the highest number of HDLI cases (n=188). Further programs are operating to identify various health effects including lung injury which may be associated with the use of HD. Not only national agencies, but also pertinent environmental health societies should cooperate in the necessary investigations so that this tragedy can be properly addressed and future incidents concerning chemicals and chemical-containing products can be prevented.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.365-374
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• 2016

Objectives: Studies are needed to examine the characteristics of health effects reported by people who used humidifier disinfectant (HD), including the distribution of victims. Methods: We analyzed the distribution of health effects including lung injury that were asserted by a total of 699 individuals who registered with the first through third national programs to determine health effects associated with the use of HD. Results: We found that HD-associated lung injury (HDLI) occurred every year from 2002 through 2011, and in 2011 for 37.2% (n=96) of the total of 258 clinically evaluated HDLI victims. More than half of the victims responded that they were victimized between 2010 and 2011. This was consistent among all classifications by sex, age, HD brand and HD chemical ingredient. Conclusion: This study assumed that the major reason for the outbreak of the health effect between 2010 and 2011 could be the variations in concentrations and physical properties related to polyhexamethylene guanidine (PHMG). Further studies are necessary to examine if some factors related to the chemical disinfectants contained in HD brands may have caused the massive outbreak of health effects including HDLI.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.312-323
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• 2020

Objective: This study aimed to summarize the physiochemical properties, toxicity, and legal regulation of chloromethylisothiazolinone (CMIT) and/or methylisothiazolinone (MIT), review the health effects caused by exposure to CMIT/MIT, and evaluate the individual association of lung injury with the use of humidifier disinfectants (HD) containing a mixture of CMIT and MIT. Method: A literature review was conducted by searching keywords such as CMIT, MIT, health effect, dermatitis, asthma, and lung injury, either singly or combined. Results: Both CMIT and/or MIT were found to be associated with the development of several types of adverse health effects. In particular, respiratory diseases including asthma, nasal symptoms, cough, and rhinitis were caused by the use of products including CMIT or/and MIT. The mixture of CMIT/MIT has been banned in cosmetics. As of the end of 2017, nine patients who were confirmed to have HD associated lung injury (HDLI) were found to have used only an HD brand containing CMIT and MIT. Their responses regarding the name of the HD used could be trustworthy based on the short duration of HD use (less than six months) before the onset of HDLI and frequent use of HD per day. Conclusion: According to the toxicity and HDLI cases, the use of HD containing CMIT and /or MIT can cause fatal lung injury. Further study with manufacturers' assistance is necessary in order to obtain more clear evidence on the causal relationship since HDLI cases are being reported continuously.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.107-114
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• 2018

Objectives: The objectives of this study are to describe strategy for exposure assessment of humidifier disinfectant (HD) used in the national program to associate the use of HD with lung injury. Methods: Strategy and method employed to evaluate HD use characteristics were developed to associate health effects including HD associated with lung injury (HDLI). We developed HD-specific questionnaire to assess potential HD exposure, which was consistently used in the national program. Trained environmental health scientists visited the residences of registered subjects and investigated HD use characteristics. Results: Major HD exposure related variables were type of HD brand/s used; HD volume added to the humidifier, frequency of HD addition, and time spent in room/s with the humidifier; duration of HD use in the household in average months/year, weeks/month, and days/week; average sleeping hours in a room with an operating humidifier containing a disinfectant; number of HD brands used and type of HD; average distance of the bed from the humidifier in meters. Conclusions: We concluded that estimated airborne HD concentration was significantly associated with the risk of HDLI.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.513-520
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• 2021

Background: Benzalkonium chloride (BKC) has been extensively used as a preservative in industrial products and in hygiene, medical, and cosmetic applications. Humidifier disinfectant (HD) products containing BKC have been used in South Korea. Objectives: This study was aimed to review types of products containing BKC, to summarize the regulations in the US, EU, Japan, and South Korea, and to review the health effects associated with the use of HD. Methods: We reviewed and summarized documents which were searched through PubMed and Google Scholar with the key words: BKC and asthma/contact dermatitis, humidifier disinfectant-associated lung injury (HDLI), and more. Results: Regulations in most countries including South Korea do not allow its use as disinfectants in spray-type of products for medicine, cosmetics, and household products. Two types of HD containing BKC (800~1,270 ppm) were marketed in South Korea from 1996~2003. Health effects reported from people who used products containing BKC were allergic contact dermatitis, erythema, and respiratory disease, including asthma. Two people who responded as HD users containing BKC only were confirmed to have developed asthma. HD-associated lung injury (HDLI) was reported by consumers who used both HD containing polyhexamethylene guanidine (PHMG) and HD containing BKC. Conclusions: In conclusion, the use of BKC as a biocide has to be controlled considering the route and pattern of exposure. Products containing BKC as preservatives were reviewed with exposure routes and sites in the human body such as skin, eyes, and the respiratory tract. HD containing BKC was clinically evaluated to be associated with asthma.

• Journal of Environmental Health Sciences
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• v.42 no.3
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• pp.147-159
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• 2016

In South Korea, many cases of humidifier disinfectant-associated lung injury (HDLI) have been reported among people who used humidifier products containing humidifier disinfectant (HD). The objective of this study is to characterize exposure to HD among a total of 221 HDLI patients who used HD. Information and data on the HDs used were collected through a structured questionnaire and home environmental investigations. The conditions of these 221 HDLI patients were clinically confirmed to be caused by the use of HD. Children aged under 5 years old made up the highest proportion of HDLI cases (n=125, 56.6 %), followed by pregnant women (n=35, 15.8%). Forty-three percent (n=95) of the victims died. There were three cases of fetuses and 35 pregnant women among the victims. The number of HDLI patients who used only the Oxy Saksak brand of HD was found to be 85 (38.5%), followed by the HD brands Cefu (n=24, 10.9%), Lottemart Wiselect (n=9, 4.1%) and Aekyung (n=3). Patients who exclusively used HD brands containing polyhexamethylene guanidine phosphate (PHMG) (n=13, 55.7%) as an active ingredient made up the largest share, followed by those who exclusively used HD containing only oligo(2-(2-ethoxy) ethoxyethyl guanidinium (PGH) (n=24, 10.9%) and by those who only used a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (n=3, 1.4%). HD products containing PHMG were found to be the most commonly used among the confirmed HDLI patients. Three exposed fetuses who never used HD after birth developed lung injuries, indicating a probability of exposure to HD during gestation. All HDLI patients responded that they used HD while sleeping and for longer than 10 hours per day. In conclusion, the development of HDLI was clinically found to be associated with the use of several HD products containing PHMG, PGH and CMIT/MIT.

• Journal of Environmental Health Sciences
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• v.47 no.3
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• pp.193-204
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• 2021

Objectives: In January 2021, the former heads of the manufacturer SK Chemical and the vendor Aekyung were acquitted for manufacturing and selling humidifier disinfectant (HD) containing 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT). In this article, we analyzed the rationale used in this judgement in the light of scientific consideration. Methods: The sentencing document for the judgements was obtained from the Korea Supreme Court Service. In particular, the judgements made by the court related to the toxicological and individual association with HD perspectives were discussed based on scientific evidence. Results: The ruling stated that the necessary conditions for causality between CMIT/MIT and such diseases were not met based on the fact that asthma and lung damage were not found in the inhalation exposure animal experiments. The judgment overlooked the inevitable limitations of using animal experiments for verifying health effects in humans, which are often inconsistent with the observations in animals. Among 11 governmentaffirmed lung injury cases with CMIT/MIT usage, three patients' humidifier disinfectant-associated lung injury (HDLI) pathology proved that CMIT/MIT could cause lung injury similar to that caused by PHMG and PGH. In addition, five children showed decreased lung function related to damage caused by humidifier disinfectant exposure. Conclusions: We conclude that there is sufficient evidence supporting the assertion that HDs containing CMIT/MIT cause lung injuries, including asthma, contrary to the court's decision.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.111-122
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• 2021

Objectives: There was a judgment of acquittal for the manufacturer SK Chemical and the vendor Aekyung regarding humidifier disinfectant (HD) containing 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT). The rationale used in this judgement is discussed here in the light of scientific consideration. Methods: The sentencing document for the judgements was obtained from the Korea Supreme Court Service. In particular, the judgements made by the court related to the risk of HD and external and internal exposure to CMIT/MIT are discussed based on scientific evidence. Results: Rendering a determination in a criminal trial of insufficient evidence of causation, the court dismissed the prosecution's motion that humidifier disinfectant-associated lung injuries (HDLI) and asthma were associated with the utilization of these products. However, CMIT/MIT, a strong sensitizing and corrosive substance, has been reported to be associated with brain toxicity, allergic contact dermatitis, and asthma. Furthermore, the judgment did not consider total consumption amounts or the cumulative dose of CMIT/MIT in the humidifier. Lastly, there are several cases supporting the fact that exposure to water-soluble substances including CMIT/MIT can cause lower respiratory tract diseases. In addition to cases of asthma among the workers exposed to CMIT/MIT, we identified lung injury victims who were exposed to HDs exclusively containing CMIT/MIT. Conclusions: We conclude that there is sufficient evidence supporting the assertion that HDs containing CMIT/MIT cause lung injuries, including asthma, contrary to the court's judgement.

• Journal of Environmental Health Sciences
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• v.42 no.3
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• pp.141-146
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• 2016

In South Korea, many cases of humidifier disinfectant-associated lung injury (HDLI) have been reported among people who used humidifier products containing humidifier disinfectant (HD). The objectives of this study are to estimate both airborne HD concentration in the room where HD was used and the amount of humidifier disinfectant absorbed into the respiratory system. Information and data on the HDs were collected using a structured questionnaire and home environmental investigations include the volume of HD (ml) and hours used per day, concentration of disinfectants contained in the HD brand (${\mu}g/ml$), volume of the room ($m^3$), assumed ventilation rate ($m^3/hr$) and breathing rate assumed ($m^3/hr$). We used children aged under five years old as a sample and estimated both airborne HD concentrations and amount of HD absorbed into the respiratory system. The estimated airborne concentration of HD in the room ranged from 68 to $369{\mu}g/m^3$ for PHMG (polyhexamethylene guanidine phosphate) and from 16 to $239{\mu}g/m^3$ for PGH (oligo (2-(2-ethoxy) ethoxyethyl guanidine). The amount of HD absorbed in the respiratory system per day was estimated to range from 227 to $1,225{\mu}g$ for PHMG and from 53 to $794{\mu}g$ for PGH. In conclusion, a great amount of HD was likely absorbed into respiratory system, likely beyond the level of the capacity of the immune system to remove the HD absorbed.