Chernobyl accident - 15 years later
By J.M. Cuttler
April 26 will be the 15th anniversary of the tragic Chernobyl accident and of the immediate, very strong
reaction of fear and outrage throughout the world. Many people expected the radiation from the
destruction to cause millions of cancer deaths and abnormal babies. This did not happen! And the facts
we have today show it.
What new information do we have? Well, the United Nations Scientific Committee on the Effects of
Atomic Radiation (UNSCEAR) finished a 1220-page report and gave it to the UN General Assembly last
September. The title is: Sources and Effects of Ionizing Radiation. It took the 146 committee members
and staff, from 21 countries, six years to collect and study the facts in 5400 documents and write the 20page summary and ten annexes of technical details. This is the most believable information, and it was
written by an independent organization.
How does the UNSCEAR 2000 Report help us understand what happened at Chernobyl? It gives the
facts on the health effects caused by the radiation. It also compares the amount of radiation an average
person gets from many natural sources and from human-made sources, because both kinds act in the same
way on living cells.
This report shows that the amount of natural radiation received each year by many people who live in
some places of the world is many tens and hundreds of times more than the world average natural dose of
2.4 millisieverts (240 millirem). Yet these people do not have more cancers or abnormal babies.
Of the 134 Chernobyl employees who became ill from radiation, 28 died from radiation sickness and two
died from fire and falling objects – the others got well. Many emergency workers came to the station to
take away radioactive debris, so the operators could use the other three reactors. The UNSCEAR
scientists did not find more cancers or leukemias, among these 381,000 clean-up workers, than happen
naturally. The authorities moved 116,000 people away from their homes in 1986, and 220,000 more
people afterward, to stop them getting a lifetime (70-year) amount of radiation that would be more than
double the world natural average, even though many people live very healthy lives in areas that are much
more radioactive.
Careful health screening of all the people in the Chernobyl area began in 1986. Nothing like this existed
before. So far, this screening has identified a total of about 1800 thyroid cancers. Before the accident,
the incidence of thyroid cancers noticed was ~0.2 per 100,000 children in Belarus and Ukraine
(unpublished); no data are available from Russia. The highest incidences in 1987-1998: Belarus 17.9,
Ukraine 4.9 and Russia 26.6 per 100,000 children. Does it mean these cancers were caused by the
accident? Normally, it takes ten or more years for cancers to develop, if radiation is the cause, but half of
these were found sooner (in Russia in the second year after the accident: 9.1 cases per 100,000 persons).
Also, the number of these cancers is not higher in areas with more radiation. Could they be occult (small,
silent) thyroid cancers? These happen naturally, and rarely cause medical problems. Typically, there are
many thousands of such thyroid cancers in a population of 100,000. The number varies according to
geographic location and depends on many different factors. In the USA there are 13,000 per 100,000
people (28,000 per 100,000 in Hawaii). It is not reasonable to imply an increase in cancer after the
accident if there was no screening before.
The US National Council on Radiation Protection says, “available human data on low dose I-131
exposures have not shown I-131 to be carcinogenic in the human thyroid.” The National Cancer Institute
did a 14-year study of thyroid cancers found all over the United States, in the thirty-year period after the
hundred A-bomb tests in Nevada, in the 1950s and early 1960s. The 1997 report compared the number in
each area with the amount of radiation, and did not find any evidence to connect thyroid cancer to this
radiation. So, it seems that the 1800 thyroid cancers, discovered in the Chernobyl screening, were not
caused by radiation.
How does the UNSCEAR report end? The scientists say there were no increases in cancers or deaths
because of radiation; the leukemia is not higher, even for the clean-up workers, and the scientists have no
evidence of other non-malignant sicknesses from radiation. There were many psychological reactions,
but these were caused by fear of the radiation, not the actual radiation. So they conclude that there is, in
fact, no reason for anyone to live in fear of health problems from the Chernobyl accident. People
received radiation similar to, or a few times more than, the average global natural amount, but hundreds
of times less than the natural radiation that many healthy people receive every day in some parts of the
world.
So what important lessons can we all learn from these facts? We can see that many people receive large
amounts of (natural) radiation during their entire lives, and their health is no worse than all the others who
receive much smaller amounts of radiation. We might wonder what all the fuss is about. While the
Chernobyl accident was very serious – it killed 30 employees and injured some others – we can compare
it with other serious industrial accidents, such as fires, coal dust and natural gas explosions or oil refinery
accidents.
The very important difference is the tremendous fear that many have of small doses of radiation, which
our senses cannot feel. This fear comes from the information given to us, for half a century, that any
amount of radiation causes abnormal babies and cancers, which appear years later. In addition to the
great emotional stress of this fear, 340,000 people were moved from their homes causing even more stress
and huge costs for the countries affected. This new information we have shows us there is no reason to be
afraid of low doses of radiation.
Nuclear plants are safe. Scientists and engineers gather and share the information from all accidents, and
they look for ways to make their plants even safer. Operators keep looking for ways to work more safely.
So people in nearby towns have no reason to live in fear.
If people recognized these facts and changed their notions about radiation, then nuclear plants would
become a more important source of reliable and environmentally friendly energy for humanity. And
radiation would be used more and more in industry and in medicine for a better standard of living and
health.
The International Commission on Radiological Protection (ICRP) and all the organizations, that control
the amount of human-made radiation we get, ought to study carefully the scientific facts in the
UNSCEAR 2000 Report on the amounts of natural radiation. They should resolve the contradictions and
uncertainties in their guidelines and standards with what nature gives us every day. This would help
remove the myths and reduce the fear that blocks the path to our use of nuclear technologies to improve
the quality of human life and the state of the environment.
References:
1. UNSCEAR Focuses on Chernobyl Accident in General Assembly Report, Press Release No:
UNIS/UNSCEAR/1, June 6, 2000: http://www.un.org/ha/chernobyl/unsceare.htm
2. Sources and Effects of Ionizing Radiation, The UNSCEAR 2000 Report – Summary
http://www.cns-snc.ca/branches/Toronto/radiation/UNSCEAR2000Report.rtf
3. Moosa M, Mazzaferri EL. Occult Thyroid Carcinoma. Cancer Journal 10, No. 4, Jul-Aug 1997:
http://www.fr.embnet.org/agora/journals/cancer/articles/10-4/moos.htm
4. Induction of Thyroid Cancer by Ionizing Radiation, National Council on Radiation Protection,
Report No. 80, 1985, Chapter 4 Human Experience after Exposure to Iodine-131
5. Brown RA. Bomb Fallout and Thyroid Cancer: Statistical Sheep in Real Wolves’ Clothing,
1997: http://www.srv.net/~russb/thyroid/index.html
6. NCI Releases Results of Nationwide Study of Radioactive Fallout from Nuclear Tests, Press
Release, National Cancer Institute, Bethesda MD, August 1, 1997:
http://rex.nci.nih.gov/INTRFCE_GIFS/MASSMED_INTR_DOC.htm
Dose Per Year
mSv Rem
50
5
Guarapari beach, Brazil: up to 790 mSv
Ramsar, Iran: up to 700 mSv
Southwest France: up to 88 mSv
To More Than 700 mSv
mSv
1.0
Rem
0.10
0.8
0.6
0.4
0.08
GLOBAL AVERAGE
INDIVIDUAL
WHOLE BODY
RADIATION DOSE
(Each Year)
Medical
Diagnostics
0.06
0.04
NATURAL BACKGROUND RADIATION
Lower End of Natural
Background Radiation
40
4
Kerala beach, India: up to 35 mSv
30
3
Araxá, Brazil: up to 25 mSv
20
2
Sweden: up to 18 mSv
0.2
Adapted from Z. Jaworowski's
paper at the "International
Conference on Radiation,"
Teheran, Iran, Oct 18-20, 2000,
based on UNSCEAR figures.
0.02
Nuclear
Explosions
10
1
US Rocky mountain states: 6-12 mSv
Chernobyl
0
Nuclear Power
Evacuated land near Chernobyl: 6 mSv
US Capitol & Grand Central Station, NYC: 5 mSv
0
1940 1950 1960 1970 1980 1990 2000
YEAR
World average: 2.4 mSv
San Francisco, US Gulf states: 0.8-1.2 mSv
0
0
Figure 1. Comparing amounts of radiation from natural sources and human-made sources