Working Safely in a Lab

A hazard is anything that may cause harm. 

A risk is the likelihood that the hazard causes harm. All hazards have an associated risk. 

For example, a Bunsen burner is a hazard because you may burn yourself on the flame. The risk of burning yourself on a Bunsen burner flame is low because you only switch it on during the experiment. 

We can assess the size of a risk by looking at how many people in a given group exposed to the risk are harmed. 

For example, if 10 \, 000 people are exposed to harmful radiation and only 20 develop radiation sickness, we can evaluate the risk of radiation sickness is low. However if 8 \, 000 of these people develop cancer later in life, the risk of cancer is high.

In order to make decisions about risks, we need to evaluate two factors:

1. The likelihood of the consequences
2. The severity of the consequences

If a risk has very severe consequences but a low probability, you may decide not to expose yourself to that hazard. On the other hand, if a risk is very likely but has a small consequence, you may decide that the risk is acceptable. 

Different people may perceive the same hazard to have a different level of risk. People tend to perceive familiar risks (such as crossing the road) as low risk but unfamiliar risks (such as travelling in an airplane) as high risk. Short-term consequences of a hazard (like burning your tongue on a hot drink) are also often perceived as higher risk compared to long-term consequences (like developing lung problems from smoking). People are also more likely to accept a high level of risk when they are choosing to do something (for example, using a tanning-bed) rather than a risk being enforced upon them (for example, a nuclear power station being built nearby somebody’s home). 

There are hazards in biology, chemistry and physics laboratories.