We all hear these terms on a daily basis. So and so a chemical, physical or a biological

agent poses a risk; This or that product is a hazard or behaving a certain way is unsafe.

A lot of the time “hazard” and “risk” are freely used to mean the same thing. However

they are not. Hazard is the potential to cause harm. Risk

on the other hand is the likelihood of harm in defined circumstances.

But what does this actually mean? Let’s look at two examples

First, Potassium Dichromate: it sounds scary and it is indeed a hazardous substance that

is both toxic and carcinogenic. It is used in some cases to analyse exhaled

breath for alcohol. For this purpose it is sealed in a tube. Therefore although it is

intrinsically a hazardous substance, if used and managed as described, it presents little

or no risk to people or the environment. Now let’s look at the opposite case. Flour

would not be considered by many to be a hazardous substance. However, if a baker were to be

exposed over a period of time to airborne flour, he/she could develop dermatitis, conjunctivitis,

rhinitis and even asthma. So even something that is considered a low

hazard can present substantial risk and vice versa.

Risk is always a probability, influenced by the level of exposure. To evaluate the risk

we have to take many factors into consideration. How, where, how much and how long one can

be exposed to the hazard are all things to be taken into account.

Toxicological research can map the potentially harmful properties of a product, be it chemical,

physical or biological and it can also set a limit under which exposure will have no

effect. Based on this research, a risk can be calculated

based on frequency, conditions and length of exposure.

However, some types of risks are hard to quantify, either because of the complexity of a system,

like in the case of climate change, or because we still lack some of the tools to measure

it, like in the case of nano-materials. When there is no consensus on the level of

risk, policy makers sometimes who have the responsibility to decide on safety levels

apply a precautionary principle. “When sufficiently established elements

suggest that an activity is seriously expected to potentially produce irreversible damage

to health or the environment, measures should be taken even if the definite proof or the

causal link is not yet formally established with absolute certainty.” (Communication

of the EU in 2000) It is best to err on the side of caution.

Nevertheless, the precautionary decisions should remain proportional to this potential

but uncertain risk, and be reevaluated when new data become available.

Indeed The Proportionality Principle is and should be at the base of most legal thinking.

Now, how can we manage a risk? Risk can thus be managed by limiting exposure

to a danger and by the adoption of risk-reduction measures.

Prevention might be a better idea to reduce risk. For example driving has been made safer

by speed limits, the use of seatbelts, bumpers, airbags, driver assistance systems etc.

But what is considered safe? Acceptable safety levels greatly depend on where you are on

the planet, culture, socio-economic criteria and the sector. Similarly, the safety limit

adopted for a pesticide like DDT has to be balanced with its importance in safeguarding

health or food resources in some regions of the world. For each specific case, an acceptable

safety level has to be determined. This is thus not only a technical, but also a “political”

decision. Even if the previous steps are logical, what

is considered safe has to take into account the perception and acceptance of risk. These

tend to be emotional and rational at the same time. For example flying is commonly considered

a greater risk than driving although all statistics point to the contrary.

Moreover, once a perception of risk sets in, it is very hard to change. Even if all evidence

points to the opposite. For example: fear can be fuelled by debatable

science and poor or even sensationalist interpretation of a study by the media. A very limited study

that indicates that Substance A could be harmful to mice and would merit further research quickly

turns into a ‘Substance A kills’ headline. Once fear sets in, even if risk is not proven,

the precautionary principle is often pulled out of the hat.

In a nutshell, risk and perception of risk are not always aligned;

this can make political decisions difficult to make,

in these cases it is especially important to base them on facts rather than on opinions.

These facts can be gathered from scientific reports published by reference institutions,

but these reports are often written in a technical language that is not accessible to anyone

but the specialists. GreenFacts offers faithful summaries of those reports so that non-specialists

can get the information they need to build their own opinion.