Michigan’s attorney general has filed charges against three officials over contaminated water supplies in Flint.
The charges against two state employees in the environmental department have been charged with misleading the US government about the problem.
And a Flint employee is being charged with altering water test results.
Nearly 100,000 residents of the poor, mostly black city, were exposed to high levels of lead, sparking an outcry.
“They had a duty to protect the heath of families and citizens of Flint and they failed,” said Michigan Attorney General Bill Schuette.
He told reporters the three individuals would face a mixture of charges including tampering with evidence, conspiracy and misconduct in office.
The two state Department of Environmental Quality employees could face up to five years in jail.
The other man charged is a local water treatment supervisor.
Mr Schuette said the charges were just the beginning of the investigation and more charges were expected with “nobody off limits”.
There have been calls for Michigan’s Republican Governor Rick Snyder to step down over the crisis.