Box 1.

Learning points

1. Emergency medical services, including the despatch centre, need to be vigilant of the possibility of a mass casualty event if there are requests for multiple ambulances from the same location.

2. Consider equipping paramedics with a handheld portable pulse carbon monoxide (CO) oximetry for rapid diagnosis and treatment of patients with CO poisoning.

3. Increase awareness of CO poisoning at work sites and consider installation of CO detector in high-risk confined areas involving machinery that can generate CO.

4. Coordinated and prompt notification, and alerts to relevant regulatory and response agencies will help prevent escalation of the incident.