This study belongs to the field of the lead contamination in housing. It aimed to estimate the prevalence of dwellings with lead hazards and to identify the determinants of lead contamination of interior floor dust. Data from the Plomb-Habitat survey (2008-2009) were used; 1834 rooms within 484 housing units were investigated. The sample was drawn from a complex sampling design that provided a sampling weight for each dwelling. Our approach had 4 steps. First, data were checked before to carry out the statistical analyses. Second, lead levels in tap water, in interior coatings, in outdoor children's play areas and also in interior floor dust were estimated. Third, the contribution of numerous sources that may contaminate the dust were jointly assessed. An unweighted multilevel model on survey data was used to estimate the source contributions; rooms were the level-1 units and dwellings were used as level-2 units. Fourth, a Monte Carlo simulation study was carried out to make sure that our adjusted model was accurate. We provide for the first time a look at the state of lead contamination in French housing. We showed that about lead levels in tap water, in interior floor dust, in interior lead-based paint and for outdoor play areas, lead hazard occurs in approximately 2,5 %, 0,21 %, 24,5 % and 1,4 % units respectively. Moreover we found that floor dust of the landing of an apartment was the main contributor in lead contamination of interior floor dust. Finally, based on real survey data, we showed that a not suitable weighting for level-2 in a multilevel model leads to biased estimators. It would be interesting now to define what are homes with global lead hazards and to propose a protocole enables us to bring out easily the global lead hazard of a dwelling. Moreover it would be useful to study more precisely the pathway of lead contamination in housing between the different environmental medias and to generalize findings about the weighting at level-2 in a multilevel model on survey data.
