A team of researchers has proposed a theory of “sudden body fluid vaporization” as the cause of death for the victims, and it’s as chilling as it sounds. It’s hard to fathom a more harrowing demise than being claimed by a volcano, but a recent study might just redefine that horror.

Researchers from Federico II University Hospital in Naples, published in PLOS One, suggest that some victims of the Mount Vesuvius eruption met their end as the intense heat caused their blood to boil and their skulls to subsequently explode. When Mount Vesuvius erupted in 79 AD, it unleashed volcanic ash, gas, and rocks up to nearly 21 miles away, with molten lava flowing for two days. Those who remained in nearby cities like Oplontis, Pompeii, and Herculaneum faced gruesome deaths if they failed to evacuate in time.

The new research, focusing on victims in Herculaneum, located just four miles from the volcano, sheds light on particularly gruesome deaths. About 300 individuals sought refuge in 12 waterfront chambers along the city’s beach but were tragically trapped when the eruption occurred. Excavated in the 1980s, their remains revealed a haunting scene.

Analysis of skeletal remains unveiled a mysterious red and black residue on bones, inside skulls, and in the ash surrounding the victims. Testing showed traces of iron and iron oxides, suggesting blood vaporization. The researchers concluded that the extreme heat likely caused instant death through heat-induced hemorrhage, intracranial pressure increase, and subsequent bursting of skulls.

The waterfront chambers, bombarded by volcanic ash and heat, likely turned into infernos, with temperatures estimated to have reached around 500 degrees Celsius (932 degrees Fahrenheit). Several skeletons exhibited skull damage and staining consistent with “recurrent skull explosive fracture.”

In contrast, those who perished in Pompeii, located a bit further from the volcano, met a similarly instant demise but without the gruesome details. Lead scientist Pierpaolo Petrone explained that the lower temperatures—about 250-300 degrees Celsius—were sufficient to kill instantly but not enough to vaporize flesh.

While the hypothesis is undeniably grim, it holds significant implications for future research on the still-active volcano. Mount Vesuvius historically erupts majorly every 2,000 years, with the last event nearly 2,000 years ago. This suggests another catastrophic eruption may occur sooner rather than later, posing significant risks to the millions of people residing nearby.