The eruption of Mount Vesuvius in the ancient city of Pompeii is one of history’s most iconic volcanic eruptions but new research has shown that the Pompeiians had a lot more to worry about than some big flaming mountain.

The Romans were at the forefront of civilisation and most places in their empire had magnificent buildings, completed roads and complex water systems but it turns out they hadn’t quite got everything sussed. Research gathered by Toxicology Letters has found that the pipe system contained dangerous levels of the chemical antimony which can cause lead poisoning in the water. It has been suggested by a small number of historians that part of the decline of the Roman Empire was partially caused by these pipes and the illness it brought to the inhabitants of the Roman colonies. Antimony is naturally produced around volcanoes and the Pompeii pipe antimony most likely came from Mount Vesuvius and intercepted the water system.

Archaeological chemistry expert Kaare Lund Rasmussen analysed a pipe fragment from the ancient city and said,  “The [antimony] concentrations were high and were definitely problematic for the ancient Romans. Their drinking water must have been decidedly hazardous to health”.

Antimony poisoning can cause reactions such as vomiting, diarrhoea and dehydration. In extreme cases, it can also affect the liver and kidneys, and even cause a heart attack.

So the ultimate lesson here is not to build a city near a volcano- it’ll either erupt and wipe out the city or poison you with antimony.