Published by
Abstract
In this article, we present a medico-legal case involving a domestic gas oven explosion that resulted in suspected traumatic brain injury (TBI) without direct impact or radiological evidence. The individual developed persistent and progressively worsening neurological and psychiatric symptoms. As independent consultants, we conducted a two-part investigation: blast simulation to estimate overpressure at head level, and a literature review to compare against known thresholds for blast-induced brain injury. Our findings showed that the estimated overpressures exceeded documented injury levels in both animal and human studies. The case, spanning over six years and multiple legal teams, was ultimately resolved through settlement. This work underscores the need to recognise non-traditional brain injury mechanisms in civilian settings and demonstrates the value of biomechanical analysis in supporting scientifically grounded conclusions in complex medico-legal cases.
Introduction
When people imagine traumatic brain injury (TBI), they often think of sports collisions, car accidents, or military combat. Fewer would consider a quiet kitchen or a gas oven as a potential source. Yet, in a recent medico-legal case in North America, that assumption was challenged. A domestic gas oven explosion left an individual with symptoms of brain injury, despite the absence of any direct head impact or visible signs on brain scans.
This article describes our forensic investigation into the plausibility of such an injury, using engineering simulation and biomedical evidence. The findings demonstrate that blast-induced brain injuries (often associated with warfare) can occur in civilian home environments and can be easily missed by standard clinical methods. For legal professionals, medical assessors, and insurers, this case highlights a growing need to recognise and evaluate invisible but scientifically valid injuries.
The Incident
The case involved a person who was using a gas oven at home when a delayed ignition occurred. Gas had accumulated inside the oven chamber before it finally ignited, resulting in a sudden explosion and fireball. At the moment of ignition, the individual was standing close to the oven, peering inside with their head positioned between the open door and oven opening.
There was no direct impact or penetration injury. However, in the aftermath of the explosion, the individual began experiencing persistent symptoms including hypoacusis (hearing loss) plus tinnitus (ringing in ears), photophobia (light sensitivity), dizziness and sleep disturbances, which are all commonly associated with traumatic brain injury (TBI). Over the following year, more severe neuropsychiatric symptoms developed, including increasing aggression, emotional volatility, and episodes of paranoid thinking. These symptoms progressively worsened and, at times, were accompanied by intermittent suicidal ideation.
Such symptoms are often difficult to detect using standard imaging techniques, and this pattern is not uncommon in patients with TBI, particularly those whose injuries involve blast exposure or other non-impact mechanisms.
Detailed medical evaluation, including conventional scans, such as CT, showed no structural abnormalities. This created a challenge: how could a potential brain injury be evaluated or proven without visible evidence?
Our Role and Objectives
Our company, HIAP Limited, was appointed by the legal team representing the injured individual. As independent consultants, we were asked a single, critical question:
Was it scientifically plausible that the explosion could have caused a brain injury, even though there was no visible trauma or radiological evidence?
To answer this question, we conducted a two-part investigation:
1. Engineering Analysis: To calculate the intensity of the blast wave at the location of individual’s head during the explosion.
2. Scientific Literature Review: To determine whether such levels of blast wave overpressure had previously been shown to cause brain injury.
Engineering Analysis: What Happens During a Gas Oven Explosion?
Gas explosions occur when a combustible mixture of fuel (like natural gas) and air is ignited. The rapid release of energy creates a blast wave, which is a sudden and intense pressure front that moves faster than the speed of sound. In open spaces, these waves may dissipate quickly. But in confined or semi-enclosed environments (like inside an oven), the wave can become significantly amplified, especially when it reflects off nearby surfaces such as walls or, in this case, the oven door.
Using detailed photos and measurements of the oven, we developed a digital model of the event, including the estimated volume of gas involved and the position of the head at the time of the explosion. We then applied a fluid-structure interaction (FSI) method to simulate the explosion of the natural gas–air mixture within the confined space.
We conducted four different simulations under varying assumptions about how efficiently the gas mixture exploded and how much structural reflection occurred. In all realistic scenarios, the blast wave overpressure at head level ranged from approximately 140 to over 300 kilopascals (kPa).
Another critical insight from our engineering analysis was the role of reflection and confinement in amplifying the blast. When the blast wave hits nearby surfaces, such as the oven door, it reflects and combines with the original wave, producing even greater local pressures. The confined geometry of the oven cavity caused multiple internal reflections, each contributing to the total blast loading at head height.
In practical terms, this means that being close to a partially open oven during a gas explosion increases the risk of high-pressure exposure, even without flames or shrapnel.
Literature Evidence: What Level of Blast Exposure Can Cause Brain Injury?
We conducted a thorough review of published scientific studies that investigated the effects of blast exposure on the brain. These included animal models, human case studies, and occupational exposures (e.g. soldiers, law enforcement breachers, and industrial workers).
Key findings from the literature include:
• Mice and rats exposed to blast overpressures as low as 17–38 kPa showed long-term behavioural deficits and white matter damage1.
• Non-human primates exposed to blast overpressure of 80 kPa and 200 kPa showed changes in the brain, which were detectable via histopathology but mostly not detectable by MRI2.
• Human breacher trainees exposed to a single blast of 56.5 kPa showed elevated blood biomarkers linked to TBI and reported classic concussion-like symptoms3.
• Cumulative exposures to as low as 3.4–34 kPa overpressures in human subjects produced MRI and blood biomarker abnormalities and concussive-like symptoms4.
This means that even the lowest estimated blast overpressure in our oven explosion case (140 kPa) was well above the thresholds of brain injury. This evidence strongly supports the conclusion that a blast of this intensity could plausibly cause a brain injury.
Why Brain Injury Can Be "Invisible"?
What makes blast-induced brain injury particularly complex is that it doesn’t require any direct physical impact. Unlike a fall or a car crash, which involve direct contact forces, the injury in our case came from the blast wave alone. This type of trauma is classified as a primary blast injury.
When a blast wave hits the human body, it travels through the skull and brain tissues, creating rapid pressure changes. These can cause:
• Stretching and tearing of nerve fibres (axonal injury)
• Disruption of blood vessels
• Formation of microscopic bubbles in cerebrospinal fluid, which can collapse and damage surrounding tissues
These effects can be subtle and occur without skull fracture, contusion, or bleeding, and therefore may not show up on CT or MRI scans. However, the person may still experience brain injury symptoms with a range of severity. This is seen in the case we examined, reinforcing the medical plausibility of a brain injury even in the absence of visible trauma.
Medico-Legal Implications
This case has several important implications for the legal and insurance communities:
1. Brain injury can occur without impact or imaging findings. The absence of visible trauma or CT evidence does not mean an injury did not occur.
2. Blast injuries are not limited to conflict, road traffic or industrial accidents. Domestic environments, particularly those involving gas appliances, can produce dangerous pressure levels under rare but possible conditions.
3. Scientific and engineering analysis can bridge the evidence gap. When conventional diagnostics fall short, biomechanics and blast simulation provide objective, reproducible evidence that supports or refutes injury claims.
4. Symptom-based diagnosis must be taken seriously. Especially when symptoms match established profiles and there is a biomechanically plausible mechanism of injury.
It is essential that both medical and legal professionals remain open to non-traditional mechanisms of injury, especially in cases where symptoms persist and conventional tests offer no answers. Since TBI is caused by mechanical loading, biomechanical simulation and scientific evidence can help bridge the gap in understanding the effects of exposures on the brain, offering clarity, credibility, and, where appropriate, justice.
Closing Remarks
The case was ultimately resolved through a settlement more than six years after the incident, following input from multiple legal teams. The resolution was significantly informed by the biomechanical evidence we provided, which helped establish a scientifically grounded understanding of how the injury could have occurred despite the absence of visible trauma. Notably, it was the fifth and final legal team that recognised the complex nature of blast-induced traumatic brain injury and reached across the globe to engage appropriate expertise to help evaluate the case.
This case illustrates that even everyday environments like a kitchen can generate blast conditions capable of causing brain injury. A domestic gas oven, when misfiring, can generate a blast wave powerful enough to exceed thresholds known to cause brain injury. Importantly, the symptoms of blast-induced TBI can persist long after the event, often in the absence of radiological findings. This makes diagnosis and legal recognition more difficult.
As our understanding of blast biomechanics grows, it is essential that both medical and legal professionals remain open to non-traditional mechanisms of injury, especially in cases where symptoms persist and conventional tests offer no answers. Biomechanical simulation and scientific evidence can help bridge that gap, offering clarity, credibility, and, where appropriate, justice.
About HIAP: Independent Forensic Biomechanics
The authors of this article are consultants of HIAP Limited, while holding academic positions at leading UK universities. HIAP Limited is a UK-based consultancy specialising in independent, third-party biomechanical analysis for injury reconstruction and assessment, with particular expertise in traumatic brain injury.
HIAP provides expert analysis and reporting in the following areas:
• Medico-legal expert witness services, supporting injury claims across a range of contexts including workplace incidents, road traffic collisions, sporting accidents, and domestic settings.
• Helmet performance evaluation and design consultation, assisting manufacturers, safety bodies, and researchers in assessing and improving protective equipment.
• Development and application of custom test rigs for the experimental evaluation of helmet performance under real-world impact and blast conditions.
• Education and training, delivering workshops and seminars on brain injury biomechanics for legal, medical, and engineering professionals.
HIAP operates with a strict commitment to objectivity and scientific integrity and rigour. Our work combines peer-reviewed research, validated simulation methods, and evidence-based medical knowledge to support courts, tribunals, and other decision-makers.
We do not advocate for any party. Instead, our role is to deliver clear, independent, and scientifically grounded opinions to assist in the fair and accurate assessment of injury claims, especially those involving complex or “invisible” mechanisms that are not easily captured through conventional, and often costly, diagnostics.
References:
[1] Rubovitch, V., Ten-Bosch, M., Zohar, O., Harrison, C. R., Tempel-Brami, C., Stein, E., ... & Pick, C. G. (2011). A mouse model of blast-induced mild traumatic brain injury. Experimental neurology, 232(2), 280-289.
[2] Lu, J., Ng, K. C., Ling, G., Wu, J., Poon, D. J. F., Kan, E. M., ... & Ling, E. A. (2012). Effect of blast exposure on the brain structure and cognition in Macaca fascicularis. Journal of neurotrauma, 29(7), 1434-1454.
[3] Eonta, S. E., Kamimori, G. H., Wang, K. K., Carr, W., LaValle, C. R., Egnoto, M. J., & Tate, C. M. (2020). Case study of a breacher: investigation of neurotrauma biomarker levels, self-reported symptoms, and functional MRI analysis before and after exposure to measured low-level blast. Military Medicine, 185(3-4), e513-e517.
[4] Boutté, A. M., Thangavelu, B., Nemes, J., LaValle, C. R., Egnoto, M., Carr, W., & Kamimori, G. H. (2021). Neurotrauma biomarker levels and adverse symptoms among military and law enforcement personnel exposed to occupational overpressure without diagnosed traumatic brain injury. JAMA Network Open, 4(4), e216445-e216445.
Published by: