The Unexpected Effect of Mustard Gas

This haunting painting by John Singer Sargent (‘Gassed,’ 1919) shows the horrific consequences of Mustard Gas that nations used against enemy soldiers in the First World War. The hazy yellow skies permeate the atmosphere, as the wounded men make their way across the canvas, many blinded by the hydrochloric acid that survivors attested smelt of mustard, burnt garlic, or horseradishes ground in fire. It is one of the strangest inversions in history that such a deadly poison would eventually lead to one of the leading treatments of cancer in our own day: chemotherapy.

Germans had lead the way among nations in the development of applied chemistry. Getting their original impetus from the demand for dyes for fabric, scientists had created medical treatments for several diseases by the late 1800s. However, as the world’s countries began their collapse into World War I, German scientists began to put their efforts into chemical warfare. Mustard gas had its genesis from a mixture of hydrochloric acid with a solvent used in the dying process (thiodiglycol). One of the earliest attacks came from the Germans against British troops positioned in the Belgian town of Ypres on June 12, 1917. Men saw artillery shells labeled with yellow crosses, which – when they landed – vaporized clouds of “thick yellowish green,” as one soldier recalled. The gas went through leather, rubber, and cloth, blinding and burning the lungs of everyone in its wake.

Two thousand died that evening, but the damage continued to unfurl for years after, and some doctors noticed a particularly unusual effect on the bone marrow of some victims: it was desiccated, unable to make white blood cells. Only years later did scientists figure out that they could target this property against cancerous cells and stop them from growing. Chemotherapy was ultimately the result — an ironic outcome of a product originally designed to end, not extend, human life.