"Because we are always exposed to background radiation....."

We have heard nuclear industry pundits including Jeremy Whitlock, an extraordinarily well-spoken man, repeat the mantra that natural terrestrial background radiation is not harmful to human health. Furthermore, the presence of background radiation is used as an excuse to add more radiation to it!

Medical experts disagree about the safety of background radiation.

Just one example: According to the Canadian Cancer Society radon-222, a natural decay product of uranium-238 found in the soil, is the leading cause of lung cancer in Canada after tobacco smoking. Lung cancer is the cause of approximately 3,200 deaths in Canada annually.

Another natural background radionuclide, polonium-210, a decay product of radon-222 is believed now to be the main cancer-causing agent in tobacco. It gets into the tobacco leaves via the phosphate fertilizer which is used. The action is somewhat synergistic - polonium binds onto the sticky tar particles which have attached themselves to lung tissue -  the body cannot then expel the polonium, so over time it continues to irradiate the tissue, often ultimately causing a tumour to develop. The polonium is an alpha emitter so it would require internalization by breathing, eating or wound contamination to exhibit the alpha effect - which has 5000 times more energy than the alpha particles from radon. Polonium is also a gamma emitter; in fact, polonium has so much energy that it can aerosolize itself.

"Natural" uranium, U-238, is also known to be highly carcinogenic and to cause other deadly respiratory and other diseases. Uranium's radioactivity is combined with its actions, much like lead or mercury, as a heavy metal. 

The sun's rays are considered to be in the radioactive energy range - sources disagree about whether these are cosmic rays or not - but, in any case, we know that excessive exposure of especially light-skinned people results in increased wrinkling and an increased incidence of skin cancers.

We also receive internal radiation from potassium and carbon in our foods and nitrogen and carbon in the air we breath. Radioactive carbon-14 exists as one-trillionith of the carbon in the world; radioactive potassium-40 is 0.012% of the potassium in our food and water. We cannot avoid them but that does not mean that they may not be responsible for a very small proportion of the cancers people experience.

What we do know is that whenever we increase background radiation, we increase the incidences of leukaemia in offspring (Alice Stewart, 1958 and Rosalie Bertell, 1965), the increases in Down's syndrome and other genetic abnormalities. Research has shown non-statistical increases in heart disease, athersclerosis and auto-immune diseases like rheumatoid arthritis and lupus.

There is enough evidence. Enough that Biological Effects of Ionizing Radiation VII (BEIR VII), a publication of the US National Academies' National Research Council, confirmed a linear relationship of health effects all the way down to zero. Ionizing radiation is not good for ordinary human beings.