South Korean humidifier disinfectant case

The humidifier disinfectant case was an outbreak of lung diseases in South Korea caused by chemicals contained in humidifier disinfectants.

The outbreak was detected in children between 2006 and 2011, and in adults in the spring of 2011; the mortality rate in children was 58 percent, while among adults, 53 percent died or required lung transplants.[1] Autopsies and epidemiological work, followed up by animal studies, led the South Korean CDC to identify polyhexamethylene guanidine (PHMG) used in humidifier disinfectants as the cause.[1][2]

The main cause of the lung diseases was the chemicals PHMG, methylchloroisothiazolinone (CMIT), methylisothiazolinone (MIT) and oligo(2-(2-ethoxy)-ethoxyethyl)guanidinium-chloride (PGH).[3] Experiment of South Korean government found pulmonary toxicity of PHMG and PGH[4][5] PHMG and PGH caused pulmonary fibrosis when experimented on animals. On November 11, 2011, six humidifier disinfectants which contain PHMG and PGH were recovered. PHMG and PGH was banned in 2011, and new cases ceased occurring.[1][2]

However, later on, the Korea Centers for Disease Control and Prevention did not find a causal relationship that CMIT and MIT in humidifier disinfectants cause pulmonary fibrosis. This result, still, did not mean that CMIT and MIT were safe,[4] as the chemicals also affected the brain and skin to varying extents.[6] At least five victims used CMIT or MIT-based humidifier disinfectants.[7][8]

Most victims used Reckitt Benckiser's humidifier disinfectant, Oxy Ssak Ssak (옥시싹싹), which led the British firm to various court indictments in the years following 2011.[9][10][11]