Vehicular carbon monoxide poisoning in a Nigerian family resulting from converging environmental health risks and delayed recognition

Carbon monoxide poisoning (COP) represents a critical but under-recognized consequence of environmental health systems failure in low- and middle-income countries, where weak enforcement of vehicle inspection, poor road infrastructure, and prolonged traffic congestion intersect to create hazardous exposure conditions. This paper describes a near-fatal vehicular exposure involving a family travelling in southern Nigeria, where exhaust system damage, lack of immediate repair options, and sustained operation of a non-roadworthy vehicle in a poorly ventilated and congested setting likely led to toxic accumulation of carbon monoxide. Based on retrospective field reports, it presents an environmental health case study, not a clinical case report. Clinical manifestations were reported to have varied and initially misinterpreted. The adults involved in the incident recognized the possible COP only after the youngest member of the family lost consciousness. Our presumptive diagnosis of COP is predicated on the exposure history, symptom clustering, and resolution of symptoms with ventilation, as no carboxyhaemoglobin measurement or clinical evaluation was performed. Nevertheless, this presumptive case underscores how regulatory gaps, infrastructure deficiencies, and delayed recognition due to low public awareness and limited risk communication can converge to produce life-threatening exposures during road transportation. It also highlights how formal education alone does not mitigate risk in the absence of system-level safeguards and effective public health messaging. Strategies such as enforcing and strengthening routine vehicle roadworthiness inspection systems, particularly mandatory exhaust integrity checks, and public awareness campaigns are needed to prevent similar incidents on a large scale.