Graphic: Charlie Szymanski, Christine Chan, Matt Weber, M.B. Pell

Source: State agencies or CDC. Some states did not include data for census tracts and zip codes if the testing numbers were small, usually below five, to protect patient privacy. These areas appear as if no one was tested.

Data by census tract: CO, IN, MA, MD, MN, MO, WI, PA, OH, NH, OR, NYC

Data by zip code: CA, IL, MI, NM, OK, RI, SC, TX, WV, CT, IA, NY, VA, LA, NJ, AL, FL, AZ, GA, KS, TN, NC, VT, DC

Years: Data for 2012: CA (statewide), 2015: IL, NH; 2005-2011: TX, VA; 2004-2015: OR; 2005-2014: NY; 2005-2015: IN, MA, MD, PA, OH, MI, OK, RI, WV, CT, NH, LA, NJ, AL, GA, NC, VT, DC, NYC; 2006-2015: NM, IA; 2010-2014: CO, WI; 2010-2015: MO, SC; 2011-2015: MN; 2012-2015: AZ; 2011-2016: FL; 2005-2007 and 2010-2015: TN; 2005-2012: KS.

Result types: TX, WC, CT, IA, MO, MN, OR, AL, FL only included confirmed results, MA included estimated confirmed results and all other states included a mix of confirmed and unconfirmed test results.

NOTES

• All the states included children tested under the age of six except Indiana, which included children under seven.

• Iowa and Florida were only able to provide data on numbers of children who tested above 10 micrograms per deciliter.

• Massachusetts uses confirmed and unconfirmed results to estimate the number of children with elevated lead levels.

• Wisconsin’s numbers represent the percentage of children who tested with blood lead levels between 5 to 9.9 micrograms per deciliter. In addition, Wisconsin offered separate figures for children with highly elevated levels above 10 micrograms per deciliter, which are not included here. In some of the most heavily impacted census tracts in the state, 10 percent or more of blood tests came back at a 10 or higher.

• California’s state health department only provided results for the 546 zip codes where at least 250 children were tested for lead levels above 4.5 micrograms per deciliter.

• Arizona provided results for all tests and not the results for unique children.

