The chaotic state induced within a living cell when it is exposed to ionising radiation has been graphically described by Dr Karl Z. Morgan as a `madman loose in a library'.[4] The result of cell exposure to these microscopic explosions with the resultant sudden influx of random energy and ionisation may be either cell death or cell alteration. The change or alteration can be temporary or permanent. It can leave the cell unable to reproduce (or replace) itself. Radiation damage can cause the cell to produce a slightly different hormone or enzyme than it was originally designed to produce, still leaving it able to reproduce other cells capable of generating this same altered hormone or enzyme. In time there may be millions of such altered cells. This latter mechanism, called biological magnification, can cause some of the chronic diseases and changes we usually associate with old age. One very specific mutation which can occur within the cell is the destruction of the cell's mechanism for resting which normally causes it to cease reproductive activities after cell division. This inability to rest results in a runaway proliferation of cells in one place, which, if not destroyed, will form a tumour, either benign or malignant. The abnormal proliferation of white blood cells is characteristic of leukaemia; red blood cell proliferation results in what is called polycythemia vera.
        If the radiation damage occurs in germ cells, the sperm or ovum, it can cause defective offspring. The defective offspring will in turn produce defective sperm or ova, and the genetic `mistake' will be passed on to succeeding generations, reducing their quality of life until the family line terminates in sterilisation and/or death.[5] A blighted or abnormal embryonic growth can result in what is called a hydatidiform mole instead of a baby.
        Exposure to radiation is also known to reduce fertility, i.e. women become unable to conceive or give birth.
        Radiation can also damage an embryo or foetus while it is developing within the mother's womb. This is called teratogenic damage, or the child is said to have a congenital malformation rather than genetic damage. This means the damage is not automatically transmitted. For example, a deaf person, made so by a pre-birth injury, may have children with normal hearing.
        The damage done within cells by random releases of the energy of photons, alpha, beta or neutron particles can occur indirectly through an effect called ionisation. As the energised photons or particles speed through the cells, they give energy to the electrons of chemicals already within the cells, enabling some electrons to break free from the rest of the atom or molecule to which they are attached. On the macro-level this would be comparable to an atomic explosion of a magnitude great enough to drive the earth or another planet out of its orbit around the sun. What was an electrically neutral atom or molecule is split into two particles -- a larger positively charged atom or molecule missing one of its electrons, and a small negatively charged electron expelled from its orbit around the nucleus of the atom. Both are called ions and the process is called ionisation.
        The complex molecules making up living organisms are composed of long strands of atoms forming proteins, carbohydrates and fats. They are held together by chemical bonds involving shared electrons. If the ionising radiation displaces one of the electrons in a chemical bond, it can cause the chain of atoms to break apart, splitting the long molecule into fragments, or changing its shape by elongation. This is an `ungluing' of the complex chemical bonds so carefully structured to support and perpetuate life. The gradual breakdown of these molecular bonds destroys the templates used by the body to make DNA and RNA (the information-carrying molecules in the cell) or causes abnormal cell division. The gradual natural breakdown of DNA and RNA is probably the cellular phenomenon associated with what we know as `ageing'. It occurs gradually over the years with exposure to natural background radiation from the radioactive substances which have been a part of the earth for all known ages. There is evidence that exposure to medical X-rays accelerates this breakdown process.[6] There is ample reason to think that fission products lodged within the body will cause the same kind of acceleration of ageing. However, unlike medical X-rays, these radioactive chemicals damage cells by their chemical toxicity as well as their radiological properties.
        The gradual breakdown of human bio-regulatory integrity through ionising and breakage of the DNA and RNA molecules gradually makes a person less able to tolerate environmental changes, less able to recover from diseases or illness, and generally less able to cope physically with habitat variations.
        When the DNA of germ plasm is affected by radiation it can result in chromosomal diseases, such as trisomy 21, more commonly known as Down's Syndrome. Mentally retarded children, victims of Down's Syndrome, have been reported in Kerala, India, an area of high natural radioactivity.[7] Recently, cases of Down's Syndrome have been tentatively linked to women exposed to radioactive releases from the large plutonium fire at Sellafield (Windscale) in 1957.[8] While Down's Syndrome babies have long been associated with births to older women (those with higher accumulated exposure to natural background radiation),[9] the Sellafield-related cases involve women with an average age of 25 years.
        So far we have considered the types of ionising radiation, the location of the source outside or within the body, and the difference between exposures to different parts of the body or to different people of various ages and states of health. These will all be important considerations underlying standard setting. Next, we need to be able to measure radiation, i.e. to quantify exposure.