LAUSR

BACKGROUND On 15th April 2019, the fire at Notre Dame Cathedral, Paris, resulted in the melting of 410 tons of lead. Four hundred fourteen Paris firefighters were involved. For the purpose of preventive medicine, the level of lead contamination among the firefighters was assessed. This study objectives' were to describe the blood lead levels (BLLs) in the firefighters, to study the influence of some parameters such as the function of firefighters and the decrease in BLLs during the follow-up investigations. METHODS The emission of 138 kg of melted lead from the roof and spire of the Notre Dame Cathedral during the fire was estimated by the National Institute for Industrial Environment and Risks. Three categories were defined according to the estimated levels of external lead exposure and fire proximity: high (category 1, n = 170), medium (category 2, n = 151), and low (category 3, n = 93). Two to three weeks after the fire, blood samples to assess the BLLs were taken from firefighters in category 1 (N = 164) and from every female firefighter in category 1 and 2 (N = 4). When the BLL was above 50 μg/L (95th percentile of reference range concentrations for a sample of the French population), it was checked again at one month later (N = 31) and then, if still above 50 μg/L, at six months later (N = 10). RESULTS The geometric mean of initial blood lead level was 31.5 μg/L (CI 95% [27.7-35.9]; Min-Max: 7.0-307.6 μg/L). Twenty-five percent (n = 42) of initial BLLs were above 50 μg/L, versus 10% (n = 16) at 1 month, and 2% (n = 3) at 6 months. The French binding biological BLL limit value (400 μg/L for men and 300 μg/L for women was never exceeded and all BLLs decreased over time. BLLs varied according to the function occupied during the extinguishing of the fire: operators', officers' and those of unknown function. BLLs were significantly higher compared to drivers reflecting their lower distance to fire and fume. CONCLUSIONS The fire at Notre Dame Cathedral, Paris, resulted in moderate lead contamination among firefighters. Individual and collective protection measures probably helped to limit the contamination. Nevertheless, an effort could be made to improve the working conditions by rethinking the respiratory protection.