Evaluating risks and hazards

In a nutshell

Hazards and risks must be assessed when working scientifically to prevent any harm.

There are risks and hazards during every experiment.

Hazard	Something which has the potential to cause harm.
Risk	The likelihood of a hazard causing harm and how it causes harm.

The hazards and risks of common laboratory chemicals are shown below.

chemical	HAZARDS	risks
Hydrochloric acid	Corrosive, toxic and an irritant.	Can cause severe burns, eye damage and respiratory issues.
Potassium hydroxide	Corrosive, harmful and an irritant.	Can cause severe burns, eye damage and respiratory issues. High concentrations of potassium hydroxide can form a choking mist when reacted with water.
Ethanol	Flammable.	Can catch fire, which can develop into large-scale, dangerous fires.

To minimise the risks of hazards, labels are used to signify harmful substances. They are placed on the bottle that the substances are stored in.

The purposes of hazards labels are to:

Warn people about that dangers associated with a particular substance
Make people aware of the precautions they should take when handling the substance

HAZARD	DESCRIPTION	HAZARD LABEL
Harmful/irritant	The irritation to a body surface.
Flammable	The ability for a chemical to ignite and burn.
Respiratory sensitiser	Can be the cause of respiratory diseases.
Toxic	Any substance that causes harm to living organisms.
Corrosive	Visible destruction to living tissue.
Oxidising	Substances that intensify burning.

Risk is dependent on:

Frequency of exposure	There is a higher risk of harm if someone is exposed to the hazard more often.
Level of exposure	The higher the amount of hazard in an environment, the higher the risk of harm.
Safety precautions	If more precautions are taken, risk of harm is minimised.

Control measures are precautions implemented during a scientific investigation to reduce the risk of harm.

The risks of hydrochloric acid causing damage can be mitigated by: