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Clin Exp Emerg Med > Volume 11(2); 2024 > Article
Mehrpour and Sadeghi: The occurrence of unusually cold weather could contribute to the incidence of carbon monoxide poisoning
Dear Editor,
Following a gas leak from the engine room in a high school in west Iran, 70 students and staff were referred to the emergency department for medical treatment due to inhalation of carbon monoxide (CO). At first, the number of poisoned patients was estimated to be low; however, several students had symptoms after going home and were later referred to the hospital, causing the number of poisonings to increase. Simultaneously, cases of poisoning and death were reported in northeast Iran. An unprecedented cold weather recently caused the temperature to fall below −20 °C in this region. Improperly installed heaters and inadequate ventilation contributed to the production of CO in the environment. Therefore, the number of poisoned patients reached 230 within a week; the condition of 141 people was critical and 11 patients died within 1 week. Symptoms reported in the emergency medical centers included headache, dizziness, physical weakness, extreme fatigue, nausea, and vomiting. Limited literature exists on CO poisoning as a result of disasters such as extremely cold temperatures [1]. CO is a colorless, tasteless, and odorless gas commonly produced by incomplete combustion in fuel-burning devices. CO is sometimes called a silent killer because the gas is not irritating, has no color, odor, or taste and subjects are not aware they are affected. CO prevents oxygen from attaching to hemoglobin; thus, critical body organs, especially the brain and heart, can be starved of oxygen. Due to the formation of carboxyhemoglobin, the target organs are deprived of the oxygen they require and the ensuing hypoxia leads to damage and eventually death of the tissues in severe cases of CO poisoning. If the CO-poisoned patient has impaired consciousness or deep sleep, performing vital treatment measures is necessary. Lethal CO exposures are usually associated with CO concentrations as low as 1,000 parts per million (ppm) by volume [2]. Children under 5 years of age, adults over 65 years of age, and pregnant women in the first and last trimester of pregnancy are at high risk of CO poisoning [3,4].
The problem is more of a concern in developing countries such as Iran than in western countries, and a public health issue in China with a high disease burden [5]. Although CO poisoning has been extensively and well-described in the literature, the related mortality is still reported in less developed and developing countries. Snowfall, extreme temperature drop, and citizens not paying attention to safety warnings result in a significant increase in CO poisoning cases in parts of Iran that experienced significantly cold temperatures. Nonstandard heating devices such as camping stoves or heaters without a chimney or adequate ventilation are the main causes of CO intoxication. In addition, the lack of safety measures in the workplace and living conditions, especially in remote cities and villages, render those places more hazardous. However, anticipated cold snaps in developed countries such as Canada are often accompanied by extensive public health measures to prevent excess morbidity and mortality from CO poisoning. To prevent the occurrence of CO poisoning, visiting and inspecting the heating equipment in schools and education institutions are necessary. Furthermore, special attention should be given to remote areas. In addition, a home inspection contingency should be performed carefully in the same manner [6].
CO poisoning is well-acknowledged and reported in the literature; however, when a significant number of CO poisoning cases occur, management remains a challenge; thus, implementing effective preventive measures is important. Raising awareness of physicians for cold-related acute CO poisoning, implementing and strengthening regulations, promoting safer alternatives, and enhancing education, are crucial steps towards mitigating the lethal effects of cold disaster-related acute CO poisoning.


Author contributions
Conceptualization: all authors; Writing–original draft: MS; Writing–review & editing: OM. All authors read and approved the final manuscript.
Conflicts of interest
The authors have no conflicts of interest to declare.
The authors did not receive any financial support for this study.
Data availability
Data sharing is not applicable as no new data were created or analyzed in this study.


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6. Mukhopadhyay S, Hirsch A, Etienne S, et al. Surveillance of carbon monoxide-related incidents: implications for prevention of related illnesses and injuries, 2005-2014. Am J Emerg Med 2018; 36:1837-44.
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