As opioid addiction has risen in recent years, racial disparities in drug arrests may be changing in their size and sources. Neighborhood conditions, like economic disadvantage and racial composition, are powerful determinants of racial differences in arrests. Overdoses and police responses to these incidents may, however, alter the neighborhood context of drug arrests, especially those tied to heroin, synthetic narcotics, and related opium derivatives offenses. This study revisits the environmental correlates of arrest disparities by conducting a neighborhood-level analysis of Black–White differences in drug possession and selling arrests by substance type across the State of Delaware. Spatial model estimates suggest economic disadvantage and racial diversity in neighborhoods substantially increase Black arrest rates. Conversely, White arrest rates grow with more calls for service for overdose incidents, racial homogeneity, and to a lesser extent, economic disadvantage within a community. Disparities in arrest also vary by substance type, as heroin arrests for Whites are most correlated with higher overdose service calls relative to White arrests for marijuana, cocaine, and other substances or Black arrests for any substance. Results underscore the need to reexamine neighborhood conditions and arrest disparities due to emerging shifts in drug use and drug law enforcement.