Farm worker’s death leads to prosecution over exposure to toxic gases

A Dorset farm owner and his two businesses have been fined for serious safety failings after a 29 year-old worker died following exposure to toxic gases.

Dorchester Crown Court heard today (23 Feb) that Matthew Pitt and David Bartlett were working at Lowbrook Farm, owned by Clifford Owen Yeatman, in Bechalwell, Blandford Forum. They were exposed to toxic gases during maintenance of an anaerobic digestion (AD) plant at the farm. The plant was developed by Biogas Nord UK, of which Mr Yeatman was sole director.

On 24 June 2009, Mr Pitt and Mr Bartlett, both from Sturminster Newton, were tasked with opening the roof of the digester tank to free a stirring mechanism which had stopped moving due to a crust forming in the tank. As they did so, they were engulfed by toxic hydrogen sulphide gas.

Both men lost consciousness and when Mr Bartlett came round he found Mr Pitt lying next to him but could not get a response. He alerted other people on site to get help and an ambulance was called. Two paramedics and two other farmworkers also suffered from the effects of the fumes. Mr Pitt was later declared dead without having regained consciousness.

An investigation by the Health and Safety Executive (HSE) found a number of unsafe practices and failings during both the construction and operation phases of the AD plant.

Mr Yeatman and his company, Biogas Nord, did not assess the risks associated with the plant in general or with opening the roof. The roof had been opened five times since March 2009, including the day of the incident, by people working for Mr Yeatman. However, it was not designed for routine removal and its opening should have been required only rarely had the plant been operating correctly.

Workers were not trained to remove the roof and did not recognise that the removal of the roof was a specialist job. The risks from substances generated in the AD process, including explosion and exposure to toxic gases, were poorly understood.

Work at height during the removal of the roof was also carried out without adequate safety precautions.

 The investigation identified that a previous similar incident had never been reported to HSE. On 1 August 2008 farm worker Joerg Grondke fell unconscious after he was exposed to toxic gas when he was replacing the clamps that held the roof seal in place.

While masks were supplied after the 2008 incident workers were never trained in their use and they were taken off once the roof was removed in the mistaken belief that the danger had passed. The masks were also not face-fitted or properly maintained.

Clifford Owen Yeatman, of Lowbrook Farm, Blandford Forum, Dorset, was fined a total of £15,000 as a director of Biogas Nord UK (Ltd) after pleading guilty to two breaches of the Health and Safety at Work etc Act 1974. He also pleaded guilty to two further breaches of the act as a partner of CO and RA Yeatman and was fined £45,000. His company, Farmergy Ltd, also of Lowbrook Farm, was fined £10,000 after pleading guilty to breaching section 42 of the Health and Safety at Work etc Act 1974. Both Mr Yeatman and his company Farmergy Ltd were ordered to share £75,000 in costs.

Speaking after the hearing, HSE Inspector Annette Walker said:

“The previous incident involving Mr Grondke should have served as a warning about the risk of toxic substances when opening the roof. If that risk had been identified and safe systems of work put in place to prevent exposure to workers, the tragic death of Matthew Pitt would have been avoided.

“While farm energy generation from anaerobic digestion is an emerging application in the UK, anaerobic digestion has been used here for several decades for treatment of sludge by water companies.

“The risks associated with access to confined spaces and the associated potential for exposure to hydrogen sulphide in anaerobic digestion facilities are well-known.

“What has happened at that farm demonstrates the importance of having safe systems of work in place, particularly for maintenance and repair work where the risk of exposure is likely to be highest. The need for specialist skills and training also has to be recognised.”

Matthew Pitt’s mother, Janet Pitt, said:

“I have still not come to terms with the loss of our son. Matthew was not just a son, but a best buddy too. We were a close-knit farming family that did everything together. We lived, worked hard and played together. All that has ended and although we carry on with our lives, behind the strong exterior lies broken hearts that will never be mended.”

Further information on the process of anaerobic digestion can be found on the HSE website at


Notes to Editors

  1. The Health and Safety Executive is Britain’s national regulator for workplace health and safety. It aims to reduce work-related death, injury and ill health. It does so through research, information and advice; promoting training; new or revised regulations and codes of practice; and working with local authority partners by inspection, investigation and enforcement.
  2. Section 2(1) of the Health and Safety at Work etc Act 1974 states: “It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees.”
  3. Section 3(1) of the Health and Safety at Work etc Act 1974 states: “It shall be the duty of every employer to conduct his undertaking in such a way as to ensure, so far as is reasonably practicable, that persons not in his employment who may be affected thereby are not thereby exposed to risks to their health or safety.”
  4. Section 4(2) of the Health and Safety at Work etc Act 1974 states: It shall be the duty of each person who has, to any xtent, control of premises to which this section applies or of the means of access thereto or egress therefrom or of any plant or substance in such premises to take such measures as it is reasonable for a person in his position to take to ensure, so far as is reasonably practicable, that the premises, all means of access thereto or egress therefrom available for use by persons using the premises, and any plant or substance in the premises or, as the case may be, provided for use there, is or are safe and without risks to health.
  5. Section 37 of the Health and Safety at Work etc Act 1974 states: “Where an offence under any of the relevant statutory provisions committed by a body corporate is proved to have been committed with the consent or connivance of, or to have been attributable to any neglect on the part of, any director, manager, secretary or other similar officer of the body corporate or a person who was purporting to act in any such capacity, he as well as the body corporate shall be guilty of that offence and shall be liable to be proceeded against and punished accordingly.”
  6. The AD plant at Lowbrook Farm includes a digester tank where cow slurry, agricultural waste and energy crops is heated and mixed by agitators to generate biogas. Biogas is rich in methane and also contains carbon dioxide and the highly toxic hydrogen sulphide. The biogas is stored in a gas-holder on the roof before it is used to generate electricity.
  7. Anaerobic Digestion (AD) is a process that uses natural bacteria in the absence of oxygen to convert organic matter into biogas and a residue known as digestate.  AD installations use anaerobic digestion to  generate  and capture biogas from a variety of biomass feedstocks including household food waste, garden waste, farm slurry, agricultural waste, waste from food processing factories and energy crops. The resulting biogas is rich in methane which is then used to generate energy. Biogas also contains Carbon Dioxide and the highly toxic gas Hydrogen Sulphide.
  8. The main physical hazard associated with biogas is its flammability creating a risk of fire and explosion if the gas is mixed with air. The main health hazard associated with biogas is exposure to hazardous substances: Methane and Carbon Dioxide are asphyxiating gases which have the potential of fatal incidents by depleting oxygen in confined or closed spaces; Hydrogen Sulphide is a very aggressive and toxic bi-product of the biogas production. Short-term single exposures can cause rapid unconsciousness and death.

Article source: