The thought of mustard gas hardly brings to mind the thoughts of a great scientific discovery. Its chemical name is 1,1-thiobis(2-chloroethane), and its chemical formula is Cl-CH2-CH2-S-CH2-CH2-Cl. It was probably first made in 1860 by Frederick Guthrie. The gas is described to have a potent smell which is a bit like mustard plants or garlic which is where is acquired its name.
During the First World War mustard gas was one of three main chemicals responsible for death and injury (phosgene and chlorine were also used as weapons). Mustard gas was used for the first time in 1917 by German forces against allied troops and it saw a massive increase in the number of casualties from chemical warfare. There was little to no protection from the effects of the chemical weapon, as it could be absorbed through the skin – gas masks were no defence.
The effects of the gas are not immediate, but several hours following exposure the symptoms may start to develop. These often included bloodshot and watery, painful eyes, even with temporary blindness in severe cases due to the chemical attack on the corneas. Skin blisters would form mostly in moist area such as the armpits and genitals and these were prone to infection when they burst. Blisters could also form in the lungs with some victims coughing up blood, and it was this lung damage which could cause chronic dysfunction or even death. It caused many casualties but limited fatalities due to open air of the battlefield keeping concentrations below lethal doses. However those who received a fatal dose could take up to 6 weeks to die a very painful death.
The more long term effects possible following mustard gas exposure are stated by the CDC as; second or third degree burns, chronic respiratory disease or infections, permanent blindness, increased risk for lung cancer (most of these with the potential for fatal complications).
Yet despite all the horror and suffering caused using this chemical weapon, an unlikely discovery was made. In 1919 it was first noted that it seemed to cause a low white blood cell count in its victims. Then much later in the 1940s, research on nitrogen mustard (which is slightly different from mustard gas) revealed that it was able to reduce the growth of tumours. This was the start of what we now know as chemotherapy for cancer treatment!
This type of discovery is quite unusual with most treatment discoveries of the modern era being thoroughly planned and tested with clinical trials following strict protocol to ensure the safety of participants. This will often begin with adaptive phase 1 clinical studies, followed by phases 2 and 3 if the results are promising. Read more about this at richmondpharmacology.com/specialist-services/adaptive-phase-i-studies