A Bristol school has been fined for failure to ensure the safety of its employees

A school chemistry technician lost parts of three fingers and ruptured his bowel when a mixture he was preparing exploded.

The technician at Bristol Cathedral Choir School was preparing a demonstration involving Armstrong’s mixture, a highly sensitive explosive mixture of red phosphorus and potassium chlorate. Bristol Magistrate’s Court heard how he had prepared the mixture many times in the past for ‘fireworks’ demonstrations.

Steve Jones, director of CLEAPSS, the school practical science and technology advisory service, said: ‘Armstrong’s mixture is an unstable explosive that is not suitable for making in schools.’

Prosecuting, the Health and Safety Executive (HSE) told the court the technician spent 12 days in total in hospital after the October 2014 incident. On Monday the school was fined a total of £26,000 and ordered to pay over £12,000 in costs.

HSE said the incident could have been avoided if the school had implemented clear management arrangements to control and review the risks posed by the chemicals used in its teaching activities.

Steve added: ‘Heads of school science departments should ask themselves “How can I ensure that an incident like this cannot happen in my department?” Focusing on risk assessments for lessons in isolation is perhaps not the most productive approach. Instead, heads of science should consider how the whole department manages risk, reviewing processes and ensuring that the safety of technicians when preparing materials for lessons and disposing of waste afterwards is not overlooked.

‘One simple control measure could be to specify that technicians only provide materials requested by teachers for activities that are in the scheme of work. Any new experiments should be reviewed by the head of department before they are used with students.

‘There are many safe and exciting demonstrations available, such as the woosh bottle, ‘cannon fire’ and the howling jelly baby. CLEAPSS members can find guidance on how to carry these out safely on the CLEAPSS website.’