Chemical safety

Level 1

Why is safety important?

In chemistry, certain substances and reactions can be dangerous to health or cause accidents. It is therefore essential to know and follow safety rules to work safely in a laboratory.

  Examples: 
- Handling an acid without safety goggles can cause burns on the skin or eyes. 
- Heating a chemical without precautions can cause splashes or violent reactions.

Basic safety rules

To work in a laboratory, you must always:

 
 
 
 
 
 

Hazard pictograms

Chemical products carry pictograms that indicate how hazardous they are. The main ones are:

Pictogramme_Corrosif

Corrosive

Destroys and eats away living tissue or matter
Pictogramme_CMR

CMR

Carcinogenic, mutagenic, reprotoxic.
Pictogramme_DangerEnvironnement

Environmental hazard

Destroys or pollutes the environment.
Pictogramme_Nocif

Harmful/Irritant

Can cause irritation, bad for health.
Pictogramme_Toxique

Toxic

Can cause death at low doses.
Pictogramme_Inflammable

Flammable

Can catch fire in the presence of heat.
Pictogramme_Comburant

Oxidising

Promotes combustion.
Pictogramme_Pression

Gas under pressure

Container under pressure.

What to do in case of an accident

In a laboratory, it is essential to know how to react quickly:

  • In case of a chemical burn: rinse the area immediately with water for several minutes.
  • In case of a splash in the eyes: use the eyewash station and inform an adult.
  • In case of fire: use the appropriate fire extinguisher and raise the alarm.
  • Never run in the laboratory to avoid worsening accidents.

Key points

  • Why is it important to follow safety rules in chemistry?
  • What personal protective equipment is essential?
  • Name 3 hazard pictograms and their meaning.
  • What should you do in case of a chemical burn or a splash in the eyes?
  • Why should you never work alone in a laboratory?

The danger of acids and bases

Acids (hydrochloric acid, sulfuric acid...) and bases (sodium hydroxide, ammonia...) are often corrosive: in contact with skin or eyes, they cause chemical burns. The more concentrated the solution, the greater the danger.

  • Always wear goggles and gloves when handling an acid or a base.
  • In case of splashes on skin or in the eyes: rinse thoroughly with water for several minutes and inform an adult.

Reading the label of a household product

Many household products are acids or bases: drain unblockers (strong base), descalers and anti-limescale products (acids), bleach... Their label bears hazard pictograms (corrosive, harmful) and safety instructions to follow.

  Warning: never mix bleach with a descaler (acid): the mixture releases a toxic gas (chlorine gas).

Storing and disposing of chemicals

In the laboratory, the storage of products follows precise rules: closed and labelled containers, incompatible products separated (acids away from bases, oxidisers away from flammables), away from heat and light.

Chemical waste is never poured down the sink: it is collected in waste containers suitable for its nature, then treated by a specialized facility.

Precautions for acid-base and acid-metal reactions

  • Acid + metal: the reaction releases hydrogen, a flammable gas. Work away from any flame and under a fume hood.
  • Acid + base: the reaction is exothermic (it releases heat) and can cause splashes. Always pour acid into water, slowly, and never the reverse.