Management Information Sheet
Incident in Science Lesson
Incident in Science Lesson
Last year a science teacher in a Norfolk High School carried out a demonstration - placing sodium in a trough of water - that resulted in a pupil suffering minor burns to her face as a result of particles of sodium hydroxide being ejected during the reaction. The pupil was standing with other pupils about 2 metres away and at a 45 degree angle to the trough containing the water.
The school had referred to relevant sections of CLEAPSS Hazcard 88 (Sodium) and believed that all necessary precautions had been taken.
It is known that the behaviour of sodium is very unpredictable and it may explode and eject particles. On previous occasions when the teacher had carried out the activity the sodium had not reacted to this extent, ejecting particles only a few centimetres, usually straight into the air.
Precautions taken included:
- using prepared piece(s) of sodium of the appropriate size (no larger than 4mm)
- placing safety screens as close to the trough as possible
- pupils wore eye protection
- pupils standing 2 m away
However, the teacher placed a paper towel on the surface of the water to slow the movement of the sodium so that pupils could observe the reaction more easily. Introduction of the paper towel increased the likelihood of an earlier, more intense, reaction, therefore increasing the risks inherent in the experiment.
The fact that the sodium was constrained and was not allowed to roam freely - as the Hazcard requires - meant that the procedure set out in the CLEAPSS model risk assessment was not followed correctly.
A civil claim has been made by the parents of the injured pupil against the County Council and the county council has admitted a breach of duty.
Actions/Lessons Learned
Heads of Science/Headteachers must ensure that: