In the Exide Technologies cleanup area, 547 residents under age 21 were found to have high levels of lead in their blood.
Some census tracts with high lead counts overlapped with cleanup focus areas, which were selected based on wind patterns, proximity to the plant and soil tests that detected high lead concentrations.
Exide clean-up area
Number of high blood lead tests per census tract, 2010 to 2014
1 - 2
3 - 5
6 - 10
11 - 18
Sources: Los Angeles County Department of Public Health, U.S. Census Bureau
Graphics reporting by Ben Poston