Robert D. Bullard likes to say that he was “dragged into” the environmental-justice movement.

In 1978 he was an urban planner in Houston, Texas, when his now ex-wife, an attorney, took a case representing a predominantly African American neighborhood that had been chosen as the site for a planned garbage dump. At her behest, Bullard did the legwork to uncover some shameful evidence: landfills in the city were almost all in black neighborhoods, despite the fact that only a quarter of Houston residents were black.