Uranium and its decay products – known as “progeny“ – are harmful to human health for two reasons:
1. Uranium is a heavy metal and – even at low levels – is chemically toxic to humans, particularly to the kidney.
2. Uranium and its decay progeny emit “ionising” radiation: energy delivered in (gamma) waves and (alpha and beta) particles, which have the capacity to disrupt the microscopic contents of living cells and alter the electrical charge of materials they contact.

How does uranium affect people's health?

Humans and the environment are exposed to uranium and its decay progeny through mining, processing and disposal of the uraniumbearing ore:

Miners are exposed to radiation from radon gas which is present in elevated concentrations in mines – especially underground mines. Workers in the processing mills where the uranium is extracted from the excavated ore are exposed to radioactive dust. Workers and members of the general public are potentially exposed to radiation from “tailings” (processed ore, managed as a solid-liquid mix in
a tailings dam). Uranium and its progeny can leach into groundwater and expose surrounding populations to the chemical and radio-toxicity, particularly when drinking
water supplies are affected.

Uranium is both a chemical toxin, a heavy metal, just like nickel or chromium, and it is a radioactive toxin. In different forms it is damaging to the kidneys and can cause
lung and bone cancer and leukaemia. Uranium is also harmful to genes.

Kidney damage
Uranium is chemically toxic to the kidneys, which are responsible for detoxification and maintaining blood pressure, salt, water and sugar balance, as well as numerous
endocrinological functions.

Cancer
Radon gas is regarded as the second most potent cause of lung-cancers globally,  after tobacco. Its hazardous nature has been well documented over decades, in multiple studies in many countries. The decay products of the gas include radioactive lead, bismuth and polonium – alpha and/or beta emitters – which are deposited in lung tissue as they decay from inhaled gaseous radon. Radium is also prevalent in dust from mining and in the waste stream. It is a gamma emitter and a cause of bone cancer, cancer of the nasal sinuses and mastoid air cells, as well as leukaemia.

Genetic damage
Uranium is also “genotoxic,” meaning that it damages our DNA. The genotoxicity of
uranium may be a combination of both its chemical and its radiological properties. While DNA damage is mostly reparable by cells, alphaparticles are more likely than
other forms of radiation to cause DNA breaks that are not readily repaired. Damaged
DNA is associated with many diseases in humans, like cancer and inheritable
disease, as well as teratogenic (abnormal physiological development) effects,
including mental retardation and birth defects. Cancer may not appear for 10–40
years (latency), although this period can be as short as 5 years for leukaemia.