(CNN)– World War I ushered in an era of chemical weapons use that lingers, lethally, into the present day. Indeed, the German chlorine attacks against French, Algerian, British and Canadian troops around Ypres — site of the war’s most relentless fighting — in April 1915 presaged a world in which weapons of mass destruction became at least a permanent background anxiety and often a source of intense terror.
World War I, which began nearly 100 years ago, linked science with mass killing and, despite preventative treaties such as the 1900 Hague Convention, created a lasting precedent. Scientific progress now brought new fears as well as hope.
The other combatant nations responded to their maximum extent, with rapidly developed mixtures of retaliation-in-kind and protective technologies and procedures. Perhaps 1 million chemical casualties were inflicted, to little overall military advantage. Although fatalities were eventually kept relatively low, at about 90,000 in total, there was, and remains, deep revulsion at slow, agonizing deaths from tissue damage through blistering of the skin caused by innovations such as mustard gas or drowning through destruction of the lungs.
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