What is risk?

Risk is the chance or probability that a person will be harmed or experience an adverse healtheffect if exposed to a hazard. It may also apply to situations with property or equipment loss.

For example: The risk of developing cancer from smoking cigarettes could be expressed as "cigarette smokers are 12 times (for example) more likely to die of lung cancer than non-smokers". Another way of reporting risk is "a certain number ,"Y", of smokers per 100,000 smokers will likely develop lung cancer" (depending on their age and how many years they have been smoking). These risks are expressed as a probability or likelihood of developing a disease or getting injured, whereas hazards refer to the possible consequences (e.g., lung cancer, emphysema and heart disease from cigarette smoking).

Factors that influence the degree of risk include:

how much a person is exposed to a hazardous thing or condition,
how the person is exposed (e.g., breathing in a vapour, skin contact), and
how severe are the effects under the conditions of exposure.