Evaluating risks

It is important to evaluate the risks in a practical procedure, and to suggest suitable precautions to reduce the risk of harm.


Hazards and risks are connected. A risk is the chance that a hazard will cause harm.

When evaluating a risk, think about factors such as:

  • the way the hazard causes harm
  • how likely it is that someone or something will be exposed to the hazard
  • how serious the effects of the hazard could be


A precaution is something that can be done to reduce a risk of harm. Different substances and different practical procedures need different precautions. A risk assessment describes the hazards and risks of harm, and what suitable precautions are needed to work more safely.

Possible precautions include:

  • using less hazardous substances
  • wearing eye protection, protective gloves or other protective clothing
  • choosing different apparatus or a different method

When suggesting suitable precautions, make sure the suggestions are appropriate to the particular procedure. For example, the risk of harm from hydrochloric acid is reduced if the acid is diluted with water, and if eye protection and gloves are worn.


Ethanol is a flammable liquid. A student wants to use a Bunsen burner to heat a test tube of ethanol. Explain one suitable precaution, other than wearing eye protection and gloves, to reduce the risk of harm in this procedure.

The student could heat the ethanol using a hot water bath, with water from a kettle. This will reduce the chance of the ethanol catching fire.

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