How dangerous cleaning the CHERNOBYL reactor roof REALLY was?

The most dangerous job in human history ever - or is it? This animated chart shows in real-time the radiation dose Chernobyl liquidators received while they had to clean up radioactive debris on the reactor roof.

On 26 April 1986 a nuclear reactor in Chernobyl exploded. Hundreds of thousands of liquidators were called upon to deal with the consequences. Approximately 5,000 of them got the assignment to get on the roof of the reactor to clean up the radioactive debris. Due to the unprecedented levels of radiation their task was limited to 90 seconds.

We created this dataviz using VIZZU, a flexible data storytelling tool currently in the making.
Vizzu allows flexible translation between any type of charts as well as diving deep into data just by manipulating charts. Our goal is to allow a dialogue with data and to empower people to work with less involvement of data analysts. In addition, during the analysis, Vizu retains the analytic steps and presents a “data story” after the analysis is done. In a word, we let your data tell the story. As we heard many times on the customer interviews and client negotiations Vizzu is like “Prezi for data”.

In this channel we share public stories we create using VIZZU.

About the data:

The units of measure for radiation are complicated so we made the easy to understand but not very precise “X-ray” as our unit. Here we talk about the average radiation equivalent to receiving one hand or foot X-ray which is about 1 microSievert.

3.6 Roentgen. Not great, not tragic - quote from the HBO show referring to the false measurement due to dosimeter went off-scale.
Smoking 1.5 packs a day for a year - not a well known fact that cigarette smoking comes with high radiation exposure due to radon accumulated in the plant from fertilizers.
Fukushima exclusion zone - the highest radiation measured in the exclusion zone of the incident for several days.
Radiation workers' max. annual dose - US Nuclear Regulatory Commission regulatory limit.
Increased risk of cancer - lowest one year dose clearly linked to increased cancer risk.
5 year limit for radiation workers - US regulatory limit.
Chernobyl liquidators' average - The average dose Chernobyl liquidators were exposed to. Most of them never went to the reactor roof.
30 years as commercial aircrew - cosmic radiation is on longer flights and greater at higher altitudes.
Astronauts on ISS (6 months), Astronauts on the Skylab 4 mission - astronauts are exposed to the radiation from the sun and cosmic rays outside of the atmosphere.
Fukushima 50's maximum dose - 50 employees remained on-site after the disaster, bar shows the highest radiation members of the group were exposed to.
Average person's lifetime dose
US limit for emergency workers - regulatory limit for radiation workers on life-saving operation.
NASA annual limit on low-Earth orbit - NASA limit for astronauts, mean value, actual limits are varying based on age and gender.
Radiation sickness - causes nausea and vomiting, headaches, and a short period of skin reddening.
Fatal radiation poisoning
Chernobyl first responders - the official death toll is 54 people, most of them are firefighters and plant workers worked on the night of the accident.
Below the Hiroshima explosion - the detonation happened on 600m, the radiation exposure on the ground would have been fatal even without the heat and pressure wave.
Chernobyl open core per hour - Radiation, the uncovered, exploded reactor emitted after the accident.

Disclaimer: We are not radiation experts. This data visualization is made for entertainment purposes only.

If you're interested in other data visualizations about radiation dosages check out these:

We used the following sources to compile the dataset:

[Samuel-vbms]

RIP first responders. They didn't stand a chance.

[BadAssEngineering]

All of the sudden, im not afraid of Radiographies and CT Scans anymore

[kitt]

“I’m told it’s the equivalent of 300 million chest x-rays”

[Mr_T_Badger]

The second most radioactive thing in the Chernobyl Exclusion Zone right now is the pile of clothing from the First Responders that is still lying in the basement of the Pripyat hospital.

[wholesomesandwich]

imagine getting a yearly dose of radiation



*in just 2 seconds*

[danadurnfordkevinblanchdebunk]

You forgot to mention that none of the "rooftop liquidators" died of accute radiation syndrome (like the first responders), but a small percentage of them may have developed radiation related illnesses later in life. The numbers are not clear. They did the best they could in a tough situation. Chernobyl was way worse than Fukushima beacuse there was no primary containment structure at Chernobyl, which is why one had to be built later. No one died from radiation exposure at Fukushima.

[Gillysaurxx]

Even with the visualizations its still hard to comprehend the severity these guys went through.

[larkermouse]

It's possibly the most dangerous 90 second job in human history, in which the people doing knew how dangerous it was.

[rounak]

1st i thought my phone is connected with Bluetooth headset after i checked i found it was off
After that i raised my volume
Finally i realised this video doesn't have sound

[JFein]

I had no idea that astronauts are exposed to so much radiation in space

[nairobi]

Small note. While the average lifetime dose may be equivalent to that of the radiation doses on the roof, we only are exposed to a very small portion of radiation on the regular, so little in fact that it no where near poses any danger to us. The situation only becomes far more drastic when your receiving that level of radiation in shorter intervals of each other instead of constantly over your lifespan.

[crissyb]

Thank you
We hear so many numbers 3.6 roentgen, 700 milli sieverts.. but it's hard to understand what those number actually mean till you explain it like this

[litefoot]

We all owe those people that went on to that roof a great deal of gratitude. And that includes all of the people involved in dealing with that terrible disaster. God bless them all, and there families.

[nfang_tk]

Yesterday was the 35th anniversary of the chernobyl nuclear meltdown

[snakeySnakeybakey]

Being a Chernobyl roof Liquidator doesn't sound like such a bad job. after all, you get to retire at 24.

[icu]

True heroes, I only hope their families were looked after for the sacrifice they made for humanity.

[marianmarkovic]

Children, and that is why we build Contaiment building before accidents happend, not after, ...

[randomstuff]

Well I am pretty sure even, assuming even if no one directly died from cleaning off the roof, their lives must have been cut by 1/5 to 1/2 in just 90 seconds

[arjyadebsengupta]

You did not clean the roof because it was not there

[heinrichhein]

Can you maybe do a version with Sievert just for the more Technical people would be really nice,