Michigan's former governor, former health director and seven others were charged on Thursday with crimes stemming from lead contamination of the city of Flint's water supply as prosecutors detailed the findings of a year long investigation.

Michigan Solicitor General Fadwa Mahmoud Nicholas Lion, former director of M DHHS, is charged with nine counts of involuntary manslaughter for each a 15 year felony and one count of wilful neglect of duty, a one year misdemeanor.

Richard Snyder, former governor of the state of Michigan, is charged with two counts of willful neglect of duty, each a one year misdemeanor.

Lion and Snyder were among the nine defendants arraigned on Thursday on a total of 42 criminal counts in Genesee County courts for their roles in a debacle that afflicted the predominantly African American city of Flint and became emblematic of racial inequality in the United States.

The criminal investigation ran parallel to civil litigation, which last year yielded a settlement worth more than $600 million for victims of the water crisis that is awaiting court approval.

Flint's troubles began in 2014, after the city switched its water supply to the Flint River from Lake Huron to cut costs.

Corrosive river water caused lead to leach from pipes, tainting the drinking water and causing a Legionnaires outbreak, resulting in nine deaths.

The contamination also prompted several lawsuits from parents who said their Children was showing dangerously high blood levels of lead, which can cause development disorders.

Snyder, a Republican who has been out of office for two years, has repeatedly apologized for the state's poor handling of the crisis.

His lawyer, Brian Linen, alleged that the prosecution of his former client was politically motivated.

Hamoud, one of the lead prosecutors on the case, said their ongoing grand jury investigation could yield additional charges.