Michigan’s attorney general Dana Nessel charged Republican former governor Rick Snyder with two counts of willful neglect related to the Flint water crisis today. The charge carries a maximum penalty of up to a year in prison. Snyder pleaded not guilty. Several former senior Snyder aides were also charged, and Nessel has said more indictments may be coming.

The charges are long overdue. In 2014, while under the authority of an “emergency manager,” appointed by Snyder, the City of Flint changed its municipal water source. Rather than buy water from the City of Detroit, which has a massive water plant roughly seventy miles south, Flint would now pump its own water from the Flint River (and eventually, the plan said, from Lake Huron).

This seemingly mundane infrastructure decision would have dramatic consequences for the impoverished city. In a decision approved by state regulators, Flint officials failed to properly treat the water coming from the new source. The water from the Flint River quickly corroded the city’s old lead pipes, putting dangerous amounts of lead and other chemicals into the water supply.