Households were recruited from January 2007 through May 2008. Recruitment was staggered over this 17­ month period to incorporate the dynamic repopulation of the city in an effort to include the maximum number of neighborhoods. Households were eligible for inclusion if the house was deemed occupied and the house was a primary residence (i.e., the location where the head of household slept ≥ 4 nights/week. Federal Emergency Management Agency (FEMA) trailers were excluded from the study. Proportionate random sampling, stratified by city planning district, was used to select 109 study households. An initial recruitment letter was hand delivered to each selected household after field staff determined that the home was occupied using a well­defined protocol developed and pilot tested by the study team. If a selected household was deemed to be ineligible, another household was randomly chosen from the relevant planning district strata. A second recruitment letter was mailed after 2 weeks if no response was received from the initial recruitment letter. Up to five recruitment letters were sent to homes deemed occupied per the study protocol. If eligible homes did not enroll after five recruitment attempts, they were deemed to be nonresponsive. Active informed consent was obtained for each enrolled household. The study was approved by the Tulane University Institutional Review Board. Data collection. Each head of household was administered a survey questionnaire by a field researcher. The questionnaire was adapted from the National Survey of Lead and Allergens in Housing [Department of Housing and Urban Development (HUD) 2001]. Field staff also recorded the home’s proximity to a major road and type of house (single­ family home, low­rise apartment, duplex, etc.). Lead sampling was conducted in accor­ dance with sampling procedures as described by the U.S. EPA (1995), HUD, and the American Society for Testing and Materials (ASTM 1997a, 1997b). Surface lead dust was collected via wipe sampling from six locations in the interior of the home. Floor samples from the kitchen, bedroom, and living room floors were taken if there was bare floor, and windowsill samples were collected from the same rooms if there was a window in that room. An outdoor sample was collected from the bare soil just outside the front door of the home; if there was no bare soil in the entrance area, a sample was taken from the middle of the yard. If there was no bare soil in either of these areas, a sample was taken from the backyard. If there was no bare soil in any of these areas, no sample was taken. Results from a soil lead survey conducted between 1998 and 2000 were obtained and used to compare the distribution of lead in the city before and Environmental lead levels after Hurricane Katrina after Hurricane Katrina. The soil lead survey sampling protocol has been described in detail previously (Mielke et al. 2005). Briefly, soil samples were collected from 286 census tracts in New Orleans from the top 2.5 cm of bare soil following standard soil sampling proce­ dures. Soil lead data for the present study were geocoded to a census tract. For the 55 census tracts with soil lead data from both studies, the results were compared to assess soil lead distribution pre­ and poststorm. Sample analyses. Dust and soil lead samples were analyzed for metals by BTS Laboratories (Waldorf, MD)—a U.S. EPA– recognized, American Industrial Hygiene Association–accredited laboratory—using U.S. EPA method 7010 with graphite furnace atomic absorption spectrophotometry (U.S. EPA 2007). The results were reported in parts per million. Statistical analyses. We assessed variables known to be associated with elevated soil and dust lead levels, including age of housing, home ownership status, race, income, and proximity of the home to a busy street. For interior lead, soil lead level was also considered. Descriptive statistical analyses were performed to examine the distribution of sociodemographic and household charac­ teristics and lead levels. Twenty­ nine missing income data points were imputed from median income level of the census tract block to which the address belonged, according to the 2000 Census (U.S. Census Bureau 2003). We used logistic regression models to estimate crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) to identify factors related to elevated soil lead levels and interior lead levels, respectively. Race, income, home ownership status, and housing located near a busy street were included in the multivariable model based on a priori consideration, as these variables have been shown in the literature to be strongly associated with lead levels. Wilcoxon signed­ rank test for paired data was run on median census tract soil lead level to explore changes in the distribution of soil lead pre­ and post­ hurricane. Homes that lacked sample data because there was no bare floor to sample, no windowsill in the designated room, or no bare soil around the property were excluded from the relevant analysis. All analyses were performed using SAS software (version 9.1.3; SAS Institute Inc., Cary, NC). Results The sample consisted of 109 homes from nine planning districts in New Orleans; thus, power estimates were calculated on the sample size of 109 households. With an exposure prevalence rate of 61.2%, an α of 0.05, and an alter­ native proportion of 0.45, study power was 92%. Response rates varied from 14.2% in the French Quarter (mainly a commercial area) to 75.6% in Lakeview. The overall response rate was 32.5%. Most respondents were Caucasian (61.5%) and had an annual house­ hold income > $30,000 (67%) (Table 1). Most of the homes were built before 1946 Village de L’ est Venetian Isles/Lake Charles Lakeview Gentilly New Orleans East Bywater Uptown N Mid City Algiers Garden District Warehouse/CBD Lower Ninth Ward French Quarter English Turn Area 0 1.5 3 6 9 12 Miles Figure 1. Map of New Orleans planning districts, with lead data sample locations indicated. CBD, Central Business District. Yellow dots indicate districts that were excluded from the analysis a priori. The blue dot indicates the district that was excluded from the analysis because of insufficient population. Green dots indicate lead sampling locations. Environmental Health Perspectives • volume 120 | number 2 | February 2012 181