hours up to 2–3 days of the exposure. The risk connected to a phosgene inhalation is based not so much on its toxicity (which is much lower in comparison to modern chemical weapons like sarin or tabun) but rather on its typical effects: the affected person may not develop any symptoms for hours until an edema appears, at which point it could be too late for medical treatment to assist. Nearly all fatalities as a result of accidental releases from the industrial handling of phosgene occurred in this fashion. On the other hand, pulmonary edemas treated in a timely manner usually heal in the mid- and longterm, without major consequences once some days or weeks after exposure have passed. Nonetheless, the detrimental health effects on pulmonary function from untreated, chronic low-level exposure to phosgene should not be ignored; although not exposed to concentrations high enough to immediately cause an edema, many synthetic chemists (e.g. Leonidas Zervas) working with the compound were reported to experience chronic respiratory health issues and eventual respiratory failure from continuous low-level exposure. If accidental release of phosgene occurs in an industrial or laboratory setting, it can be mitigated with ammonia gas; in the case of liquid spills (e.g. of diphosgene or phosgene solutions) an absorbent and sodium carbonate can be applied. Accidents The first major phosgene-related incident happened in May 1928 when eleven tons of phosgene escaped from a war surplus store in central Hamburg. Three hundred people were poisoned, of whom ten died. In the second half of 20th century several fatal incidents implicating phosgene occurred in Europe, Asia and the US. Most of them have been investigated by authorities and the outcome made accessible to the public. For example, phosgene was initially blamed for the Bhopal disaster, but investigations proved methyl isocyanate to be responsible for the numerous poisonings and fatalities. Recent major incidents happened in January 2010 and May 2016. An accidental release of phosgene gas at a DuPont facility in West Virginia killed one employee in 2010. The US Chemical Safety Board released a video detailing the accident. Six years later, a phosgene leak occurred in a BASF plant in South Korea, where a contractor inhaled a lethal dose of phosgene. 2023 Ohio train derailment: A freight train carrying vinyl chloride derailed and burned in East Palestine, Ohio, releasing phosgene and hydrogen chloride into the air and contaminating the Ohio River. See