Update on Weeks 5 and 6 of 2009 (January 26–February 8, 2009):

• The number of reported cases of carbon monoxide (CO) poisoning saw an unprecedented increase following the passage of Storm Klaus through southern France. In just four days, the number of reported CO poisoning incidents in Aquitaine exceeded the annual incidence observed in previous years;

• a new mass CO poisoning incident linked to the use of radiant heating in a church occurred in the Nord region, affecting 68 people,

• a mass CO poisoning incident linked to a gas boiler, which occurred in a school gymnasium in Savoie, exposed 27 students, 4 of whom were treated in a hyperbaric chamber.