The signs of acute chlorine gas poisoning are primarily respiratory, and include difficulty breathing and cough; listening to the lungs will generally reveal crackles. There will generally be sneezing, nose irritation, burning sensations, and throat irritations. There may also be skin irritations or chemical burns and eye irritation or conjunctivitis. A person with chlorine gas poisoning may also have nausea, vomiting, or a headache.[1][2][3]
Chronic exposure to relatively low levels of chlorine gas may cause pulmonary problems like acute wheezing attacks, chronic cough with phlegm, and asthma.[2]
Occupational exposures constitute the highest risk of toxicity and common domestic exposures result from the mixing of chlorine bleach with acidic washing agents such as acetic, nitricorphosphoric acid. They also occur as a result of the chlorination of table water. Other exposure risks occur during industrial or transportation accidents. Wartime exposure is rare.[2][3]
Humans can smell chlorine gas at ranges from 0.1–0.3 ppm. According to a review from 2010: "At 1–3 ppm, there is mild mucous membrane irritation that can usually be tolerated for about an hour. At 5–15 ppm, there is moderate mucous membrane irritation. At 30 ppm and beyond, there is immediate chest pain, shortness of breath, and cough. At approximately 40–60 ppm, a toxic pneumonitis and/or acute pulmonary edema can develop. Concentrations of about 400 ppm and beyond are generally fatal over 30 minutes, and at 1,000 ppm and above, fatality ensues within only a few minutes."[2]
The concentration of the inhaled gas and duration of exposure and water contents of the tissues exposed are the key determinants of toxicity; moist tissues like the eyes, throat, and lungs are the most susceptible to damage.[4]
Tests performed to confirm chlorine gas poisoning and monitor patients for supportive care include pulse oximetry, testing serum electrolyte, blood urea nitrogen (BUN), and creatinine levels, measuring arterial blood gases, chest radiography, electrocardiogram (ECG), pulmonary function testing, and laryngoscopy or bronchoscopy.[3]
There is no antidote for chlorine poisoning; management is supportive after evacuating people from the site of exposure and flushing exposed tissues. For lung damage caused by inhalation, oxygen and bronchodilators may be administered.[6]
There is no way to predict outcomes. Most people with mild to moderate exposure generally recover fully in three to five days, but some develop chronic problems such as reactive airway disease. Smoking or pre-existing lung conditions like asthma appear to increase the risk of long term complications.[1]
In 2014, the American Association of Poison Control Centers reported about 6,000 exposures to chlorine gas in the US in 2013, compared with 13,600 exposures to carbon monoxide, which was the most common poison gas exposure;[7] the year before they reported about 5,500 cases of chlorine gas poisoning compared with around 14,300 cases of carbon monoxide poisoning.[8]
There have been many instances of mass chlorine gas poisonings in industrial accidents.
In 2002 in Missouri, a flex hose ruptured during unloading a train car at a chemical plant, releasing approximately 16,900 pounds (7,700 kg) of chlorine gas. 67 persons were injured.[1]
In 2004 in Macdona, Texas, a freight train accident released 9,400 US gallons (36,000 L; 7,800 imp gal) of chlorine gas and other toxic chemicals. At least 40 people were injured and three died, including two residents and the train conductor.[11]
In 2005 in South Carolina a freight train derailed, releasing an estimated 11,500 US gallons (44,000 L; 9,600 imp gal) of chlorine. Nine people died, and at least 529 persons sought medical care.[12]
In 2017, in Iran, at least 475 people, including nine firemen, suffered respiratory and other symptoms after a chlorine gas leak in the southwestern Iranian province of Khuzestan.[citation needed]
In 2020, on March 6, an incident occurred at EPCL (Engro Polymer and Chemicals Limited) Port Qasim, Karachi, where over 50 people were hospitalized as a result of chlorine gas leakage. No fatalities were reported.[15]
In 2022, on June 27, a tank holding chlorine gas in the port of Aqaba, Jordan, fell and ruptured. 14 people were killed and more than 260 were injured.[16]
^ abcJones R, Wills B, Kang C. Chlorine gas: an evolving hazardous material threat and unconventional weapon. West J Emerg Med. 2010 May;11(2):151-6. PMID20823965PMC 2908650
^ abcdeWhite CW, Martin JG. Chlorine gas inhalation: human clinical evidence of toxicity and experience in animal models. Proc Am Thorac Soc. 2010 Jul;7(4):257-63. Review. PMID20601629PMC 3136961
^ abcdGerald F O'Malley, GF et al. Chlorine Toxicity Medscape Drugs & Diseases, Ed. Dembek, ZF. Updated: Dec 11, 2015
^CDC Basic Facts Page last reviewed April 10, 2013. Page last updated April 10, 2013
^Squadrito GL, Postlethwait EM, Matalon S. Elucidating mechanisms of chlorine toxicity: reaction kinetics, thermodynamics, and physiological implications. Am J Physiol Lung Cell Mol Physiol. 2010 Sep;299(3):L289-300. Review. PMID20525917PMC 2951076
^ abAgency for Toxic Substances and Disease Registry via the CDC. Medical Management Guidelines: Chlorine Page last reviewed: October 21, 2014. Page last updated: October 21, 2014
^Mowry JB, et al 2014 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 32nd Annual Report. Clin Toxicol. 2015;53(10):962-1147. PMID26624241. Page 1089
^Mowry JB, et al. 2013 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 31st Annual Report. Clin Toxicol. 2014 Dec;52(10):1032-283. PMID25559822PMC 4782684 Page 1225
Fang, Boliang; Qian, Suyun; Li, Zheng; Gao, Hengmiao; Xu, Wenmiao; Ding, Nan (10 September 2020), Case report: Acute respiratory distress syndrome and shock caused by severe chlorine gas poisoning was successfully cured by venous-arterial extracorporeal membrane oxygenation, Authorea, Inc., doi:10.22541/au.159969877.77536109, S2CID242964247
This article incorporates public domain material from Public Health Consequences from Hazardous Substances Acutely Released During Rail Transit --- South Carolina, 2005; Selected States, 1999--2004. Centers for Disease Control and Prevention.
