As part of the mandatory annual analysis of atmospheric emissions, the operator of a household waste incineration plant received on October 8, 2004 the analyses of samples extracted during the month of August, showing: considerable excess of CO (312 and 664 mg/m³ vs. a threshold of 100 mg/m³) on two processing lines (l1 and l2) and in HCl on the l2 line (571 mg/m³ vs. threshold of 50 mg/m³), along with high values of dioxins (29 and 221 ng/m³) on the two lines. Informed of these results on November 8, the local DRIRE Environmental Agency proposed issuing a formal notice to impose compliance with regulatory thresholds in addition to a monthly monitoring campaign instead of annual tests (January 2005 directives), including: tracking of atmospheric emissions and impact of dioxins within a 5-km radius (analyses conducted on milk from adjacent dairy farms, atmospheric fallout). On January 21, the DRIRE Office received the cross-check analyses of discharges conducted during December: no threshold excess on the l1 line, marked excesses of both CO and HCl (513 and 183 mg/m³) on l2, very high dioxin contents on both lines (21 and 308 ng/m³). On the same day, the Agency requested closing l2 altogether (to take effect on January 24), and ultimately suspending this line (order issued on March 16 upon recommendation of the local Hygiene Office). On February 23, the samples taken in January confirmed the facility’s malfunctions and the need to shut l2 down: 1,875 mg/m³ of CO and 680 ng/m³ of dioxins above the previous findings. The enhanced atmospheric emissions monitoring programme indicated a return to normal operating conditions on the l1 line. Monitoring was extended out of precaution and oriented towards ensuring food safety, i.e.: dioxin levels found in the soils, plants, eggs, vegetables, grazing lands and fodder. According to the experts (AFSSA, INVS), these results did not reveal any abnormal level of contamination among the various media nor an exaggerated potential health risk for neighbouring populations: in particular, the rate of dioxins in storm water collector pipes was observed to be low in comparison with typical values, the amounts found in milk were compliant with sanitary standards (which equals 3 pg I-TEQ/g of fat, i.e. the value above which milk is recalled from stores), and high concentrations in eggs from family farms attributable, following a field investigation, to local practices. According to the facility operator, an inadequate level of waste preparation (formation of “clusters”, accumulation of iron wires) would explain the poor combustion (resulting in the formation of CO and dioxins). The fluidised bed would have gradually deteriorated. The malfunction of smoke exhaust treatment using milk of lime would explain the HCl contents. Works intended to bring operations into compliance and optimise both incinerator furnaces were undertaken. The plant would start up again 3 years hence (Januar2008), and at that time the pollutant disc