Radiological terrorism has been a concern for over a decade, since the 2002 arrest of Jose Padilla and since that time there’s been a lot of preparation and planning for a radiological attack. But in spite of all of the preparations and planning there’s never been a radiological attack. The best approximation we have as to what might happen comes from an accident that happened in the city of Goiânia Brazil in 1987.
A cancer therapy clinic shut down in the city of Goiânia – a city with a population of about a million people. Unfortunately, when the clinic closed the radiation therapy source was left behind; the machine in which it was stored was later stolen by some scrap metal scavengers. As the scavengers took the machine apart they found a small stainless steel capsule that interested them – when they opened the capsule it was filled with a powder that glowed blue. They didn’t know what it was but thought it looked neat so they took it home and shared it with family and friends. Within a few days, though, people were starting to get sick – doctors recognized the symptoms of radiation sickness and contacted the national government.
Nuclide(s) and activity:
The source that had been opened up held nearly 1400 curies of Cs-137.
By the time the Brazilian government arrived on-scene the contamination had spread to a number of homes and a fairly large area had been contaminated. In addition, there was wide concern among the citizens of Goiânia, who were worried about whether or not this accident would affect their health. As a result, the Brazilian government took the following steps:
- Identified the most-contaminated people and began work to remove the radioactive cesium from their bodies
- Surveyed the affected areas in Goiânia to figure out how far the contamination had spread
- Began clean-up – a total of 5000 cubic feet of soil was removed and over 60 homes were decontaminated or demolished to clean up the contamination
- Surveyed others who were affected or who were worried about their own exposure (a total of 112,000 people were surveyed, ~ 10% of the total population)
Four people received a fatal dose of radiation, including a 6-year-old child. About 120 people had enough exposure to radiation and contamination to require medical attention and a further 250 people required significant decontamination.
People from Goiânia were shunned by other Brazilians – this is called “social stigmatization.” Pilots would refuse to fly airplanes if they had any passengers from Goiânia and truck drivers refused to deliver (or pick up) goods in the city. Sales of produce and other agricultural products plummeted due to fears of radiation, hurting Goiânia’s economy.
And a few last things to consider!
Earlier I mentioned that about 10% of the city’s population wanted to be scanned for contamination – in Goiânia that was about 112,000 people; in NYC it would be close to a million people and, in a megalopolis like Delhi, Tokyo, or Cairo the number of people showing up to be surveyed could be as much as four times as many.
Take a moment to think about this number – four million nervous and frightened people needing to be scanned for radioactivity. It took a few months to scan a fraction that number in Goiânia; if we simply scale these numbers then surveying 4 million people would require several years. That means we’ve got to put together a better process.
Using queuing theory about 1000 people can pass through a few sets of double doors (the entryway to a school gym, for example) in an hour, so a single such center can scan up to 24,000 people daily – let’s call it 25,000 to make the math easier. Scanning a million people would take 40 hours – either two days going around the clock or about a week of working 9-5. More likely there would be multiple scanning centers running, and even then it would likely take a few weeks to finish up with the stragglers as well as “frequent flyers” who show up to be scanned multiple times due to anxiety, confusion, or simply wanting to confirm earlier readings.
Extrapolating that up to a city of 40 million (with 4 million or more showing up to be scanned), 10 centers that each scan 1000 people per hour would require a full week working around the clock to complete the scanning. Since running one of these centers would require 200-300 people, this means a few thousand workers (all of whom require training and occasional exercises to practice), as well as several million dollars’ worth of equipment and supplies – to be held in reserve and maintained in the event they’re needed. So one of the lessons of Goiânia is that simply preparing for a large radiological or nuclear incident can be expensive.
Not only that, but of those 110,000 people who were scanned in Goiânia there were only 370 that required follow-up – about one person in 300, of whom only one person in 1000 (roughly) required medical attention. First, that’s a very low fraction of people being scanned, which means that those doing the scanning need to be careful not to let anyone slip through the cracks – it would be easy to let one’s attention drift for a moment and miss someone who needed help. But a small fraction of a very large number can still be a large number – in a city the size of Tokyo would still produce over 10,000 people needing attention, 3500 of whom will require some degree of medical care. That’s a lot of people to treat and to decontaminate.
There’s only so far we can push the lessons learned from Goiânia – newer technology and newer thinking about how to scan, decontaminate, and sort large numbers of people mean that we can do this faster and more accurately now than in the past. But it’s still going to be a challenge.