Carbon dioxide, a common by-product of breathing, is lethal to humans in larger doses. The standard level of CO2 that a human can live under comfortable is around <600ppm but in many cases higher levels of CO2 are exposed to humans and can cause problems ranging from headaches to death depending on the concentration of the gas.
Within confined spaces, the effects of large concentrations of carbon dioxide can rapidly affect the person within the area and can cause death or lasting damage should steps not be taken to raise confined space awareness and prevent the build-up of CO2 levels.
In May 2008, labourer Brian Wilkins, a 48 year old who worked for Sheffield Forgemasters, was killed after a large amount of CO2 was released in an underground confined cellar that he was working in.
The incident happened when the automated fire extinguishing system in the property, which uses CO2 to starve fires of oxygen, activated suddenly. An investigation after the incident found that the system had activated because Mr Wilkins had been using a petrol-driven saw to cut through old inactive cabling and the saw’s action caused smoke, triggering a sensor on the fire system.
Several other employees, including the supervisor, tried to enter the area but it was impossible to rescue Mr Wilkins safely due to the excessive levels of carbon dioxide. The CO2 caused anyone who got near the cellar to struggle to breathe and remain conscious, making rescue impossible without respirators that weren’t at hand.
As a result of Mr Wilkins’ death, Sheffield Forgemasters was fined a total of £245,000 for neglecting the requirements of health and safety laws which require employers to ensure that employees always have access to the equipment, training and instruction needed to maintain safety in confined spaces.
The fines were given for a failure to provide rescue equipment that could have saved Mr Wilkins’ life, a lack of risk assessment for the cable cutting work and failing to provide a safe system of work for Mr Wilkins to work within the confined space environment. The lack of a way to immediately isolate the dangerous carbon dioxide system was also factored into the overall fine.
After the hearing, HSE Inspector Jill Thompson said:
“This was a very upsetting incident that resulted in the needless death of Mr Wilkins. It could have been an even worse tragedy as it was pure chance that another four workers who entered the cellar in a desperate bid to save their colleague did not also perish.
“Exposure to between 10-15 per cent of carbon dioxide in air for more than a minute causes drowsiness and unconsciousness. Exposure to 17-30 per cent in air is fatal is less than one minute. Carbon dioxide is poisonous even if there is an otherwise sufficient supply of oxygen.
“The risks associated with confined spaces are well known in industry and there is an entire set of regulations dealing with controlling the risks associated with them. Multiple fatalities do occur when one person gets into difficulty in such a space and then the rescuers are similarly overcome.
“Sheffield Forgemasters had given no thought to the risks associated with the task being undertaken by Mr Wilkins, nor had they provided emergency rescue equipment.
“This case shows how important it is for companies to effectively risk assess work activities, looking at how the work will be carried out and in what circumstances.”