Nord-Pas-de-Calais is one of the regions most affected by accidental household carbon monoxide (CO) poisoning. The CO poisoning surveillance system has highlighted the significant proportion of poisonings linked to the use of coal-fired heating in the region, particularly during peak periods of poisoning outbreaks. The study aims to accurately describe the circumstances of carbon monoxide poisoning linked to coal-fired heating in order to better target future prevention campaigns. The study population consists of all cases of CO poisoning involving coal-fired heating reported to the surveillance system from September to December 2007. These cases were described using surveillance data supplemented by information gathered during telephone interviews with the affected individuals (with an 85% response rate). Of the 149 poisoning cases that occurred during the study period, 74 were due to coal heating. In 54% of cases, the appliances were purchased new, and 51% were installed by the homeowners themselves. Nearly 70% of the appliances were installed without an air intake, and 61% of the professionals who installed the appliances had not complied with technical standards regarding ventilation. Installation was relatively recent for most of the appliances in question. While the flues and appliances were maintained fairly regularly, only 50% of appliance maintenance was performed by a professional. In contrast, 70% of the flues were maintained by a professional. Finally, 56% of those surveyed reported never having been informed about CO prevention measures prior to their poisoning. This study shows that the appliances implicated in the poisoning were relatively new but suffered from poor maintenance and improper installation in terms of ventilation. These findings were used to develop prevention messages for coal users and installers of coal-fired heating appliances. (R.A.)