While we know the devastating effects of the bombing of Hiroshima during World War II, a new study claims we may be underestimating its deadly impacts. The bombing immediately incinerated 80,000 people when it was dropped in 1945, and tens of thousands more died from the radiation in one of the ugliest events in human history, and now scientists are taking a deeper look at the event.

The study, published by Brazilian scientissts in the journal PLoS One, used a technique called “electron spin resonance spectroscopy” to measures the bomb’s true radiation. They found it resulted in 9.46 grays (Gy) of radiation, an extraordinary total that would be mroe than double a fatal dose, and many times the dose you would need to get radiation sickness.

And it is a big discovery because it has uses beyond simply providing historical context. It could help us in the future should a terrorist attack happen using radiation by helping to identify who has been exposed and is in need of treatment.

“There have been major improvements in the instrumentation to make it more sensitive in the last 40 years,” Oswaldo Baffa, Full Professor at the University of São Paulo’s Ribeirão Preto School of Philosophy, Science & Letters (FFCLRP-USP), saidn ina  statement. “Now, you see digitally processed data in tables and graphs on the computer screen. Basic physics has also evolved to the extent that you can simulate and manipulate the signal from the sample using computational techniques.”