A double fatality at a popular Hampshire cider festival has highlighted the potentially lethal consequences of carbon monoxide exposure and the critical importance of expert witness evidence in determining the cause of unexplained deaths. During an inquest at Winchester Coroner's Court, specialist gas engineering evidence established that a portable gas heater used by the deceased couple was both unsuitable for indoor use and improperly connected to its gas cylinder, creating conditions that ultimately proved fatal.
The deaths of Christopher Coll, 45, and Kayleigh Coll, 38, were investigated by the Coroner following their discovery inside their campervan at the New Forest Cider Festival in October last year. The couple, who leave behind four children, had attended the festival as stallholders selling handcrafted copper wire trees.
Following the conclusion of the evidence, the Coroner recorded a verdict of misadventure, finding that the couple died from accidental carbon monoxide poisoning after operating a portable gas heater while sleeping inside their campervan.
Circumstances of the Incident
Evidence presented to the court established that the Colls had spent the evening socialising with fellow trader Alexander Huxley before returning to their white Nissan campervan as temperatures dropped overnight.
Seeking warmth, they switched on a portable gas heater before going to sleep. The heater, however, was designed solely for outdoor use and carried warnings against operation within enclosed spaces because of the risk of carbon monoxide accumulation. When the couple failed to appear at their market stall the following morning, another trader became concerned and went to investigate.
Upon opening the campervan door, the witness described being immediately confronted by what he termed a "wall of gas" accompanied by a distinct hissing sound, prompting an emergency response. Christopher and Kayleigh Coll were subsequently found deceased inside the vehicle. Medical evidence confirmed that both had succumbed to carbon monoxide poisoning.
Role of the Gas Engineering Expert
One of the principal expert witnesses during the inquest was a specialist in gas engineering and appliance safety whose forensic examination of the heater became central to the Coroner's findings.
The expert examined both the portable gas heater and its associated fuel cylinder after the incident. His investigation identified two significant safety issues.
First, the heater itself was not manufactured or approved for use within enclosed environments. Portable radiant gas heaters of this type rely upon adequate natural ventilation to disperse combustion gases safely. Manufacturers routinely warn that such appliances must never be used inside tents, caravans, campervans or residential accommodation because combustion consumes oxygen while producing potentially dangerous gases, including carbon monoxide.
Secondly, the expert discovered that the heater had not been properly tightened onto its gas cylinder.
According to the evidence presented, the connection had not been fully screwed into place, allowing gas to escape from the joint. This finding was consistent with witness accounts describing an audible hissing sound and a substantial concentration of gas immediately after the campervan door was opened.
Although escaping gas itself does not necessarily contain carbon monoxide, an improperly connected appliance may adversely affect combustion efficiency. In addition, the presence of an enclosed, poorly ventilated space significantly increases the risk that combustion products—including carbon monoxide—will accumulate to dangerous concentrations.
The expert's findings therefore provided an important scientific explanation linking the physical condition of the appliance with the hazardous atmosphere inside the vehicle.
Qualifications of the Expert Witness
Although the Coroner's Court did not publicly detail the witness's curriculum vitae, gas engineering experts who provide evidence in fatal accident investigations generally possess extensive technical qualifications and practical experience. Such experts commonly have backgrounds including:
Registration as qualified gas engineers;
Specialist training in combustion technology;
Certification relating to LPG (Liquefied Petroleum Gas) appliances;
Experience investigating gas-related fatalities and fires;
Knowledge of appliance installation standards and manufacturer specifications;
Familiarity with relevant British Standards and Health and Safety legislation.
In addition to technical competence, expert witnesses owe an overriding duty to assist the court objectively and impartially. Their responsibility is not to advocate for any party but to provide independent opinions founded upon accepted engineering principles and the available evidence. This impartiality is fundamental to the administration of justice.
Carbon Monoxide: The Invisible Hazard
Carbon monoxide (CO) is often referred to as the "silent killer" because it possesses no colour, smell or taste.
The gas is produced whenever carbon-based fuels—including propane, butane, petrol, diesel and wood—burn incompletely. In confined spaces, carbon monoxide rapidly displaces oxygen and binds to haemoglobin in the bloodstream approximately 200 times more readily than oxygen. This prevents oxygen from reaching vital organs, leading to progressive poisoning. Early symptoms frequently include: headache; dizziness; nausea; confusion; fatigue.
Victims who are asleep frequently remain unaware of exposure until they lose consciousness. Without intervention, death may occur quietly and without obvious external signs.
Expert Evidence in Coroners' Courts
Coroners' proceedings differ fundamentally from criminal trials.
The purpose of an inquest is not to determine civil or criminal liability but to establish:
1. who the deceased was;
2. when the death occurred;
3. where the death occurred; and, critically, how the death came about.
Expert witnesses therefore play a particularly significant role.
Unlike lay witnesses, who describe events they observed, experts assist the court by interpreting technical evidence that lies beyond ordinary knowledge. In this case, the gas engineering expert was able to explain:
*the design limitations of the heater;
*the consequences of operating it indoors;
*the defective connection between the heater and its gas cylinder;
*the significance of escaping gas; and the engineering factors that contributed to the fatal carbon monoxide build-up.
Without such specialist testimony, the Coroner would have been unable to understand the complex interaction between appliance design, installation, combustion and ventilation.
By Edward Price
https://en.wikipedia.org/wiki/Carbon_monoxide_poisoning
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