A foul odor overwhelmed residents in northern France on Tuesday after a chemical plant began leaking a group of substances called mercaptans reports the New York Times.
The "largely harmless chemicals" escaped from the Lubrizol factory near the city of Rouen when the production of another chemical went wrong.
It wafted over northern France late in the night and reached southern England by morning on Tuesday, a noisome cloud that roused inhabitants from their sleep with its nauseating stench. There were thousands of frantic calls to emergency services, from Normandy to Paris, with residents describing the smell of household gas or rotten eggs, but the authorities moved quickly to calm fears. […]
Often described as smelling of rotten cabbage, mercaptans are used as a marker for household gas, which is odorless, so that leaks do not go undetected. They are present in feces and some cheeses, and can cause headaches and nausea, according to the Centers for Disease Control and Prevention. Those symptoms were described by a number of people in France on Tuesday.
The fumes also crossed the English Channel and settled Tuesday over the English coastal town of Hastings, due north of Rouen.
French authorities say the fumes pose no threat to any individual’s health or safety.