President Barack Obama Saturday signed a disaster declaration for Michigan because of the contamination of Flint’s water supply. The declaration directs the Department of Homeland Security’s Federal Emergency Management Agency to coordinate disaster relief efforts.

Observers blame the state’s takeover of the financially troubled city of nearly 100,000 for the contamination, caused by the corrosion of pipes. The state largely ignored complaints about the water until late last year.

The crisis began nearly two years ago when in a money-saving move by the state-appointed emergency manager, the city switched its water supply from Detroit, which supplies water from Lake Huron, to the Flint River. That body of water was heavily polluted from years of factory waste, and corrosion control chemicals were not required at the city’s treatment plant. A boil order went into effect in October 2014, and last September, doctors began urging the city to stop using the river water after high levels of lead were found in the blood of children.

Gov. Rick Snyder declared a state of emergency Jan. 5, and the National Guard began distributing bottled water last week. An investigation also is underway to determine whether the contamination is contributing to an increase in Legionnaires’ disease cases.

flint water plant The top of a water tower at the Flint, Michigan, Water Plant is seen Jan. 13, 2016. Photo: Rebecca Cook/Reuters

Democratic presidential candidate Sen. Bernie Sanders called for Snyder’s resignation Saturday, telling the Detroit News the Republican governor’s apologies are “just not good enough.”

“I think the governor has got to take the responsibility and say, ‘You know what? My administration was absolutely negligent, and a result of that negligence, many children may suffer for the rest of their lives, and the right thing to do is to resign,’” Sanders told the News in a telephone interview from Vermont.

Snyder Friday agreed to return some executive powers to the mayor of Flint, although the Receivership Transition Advisory Board will retain broad power, the Lansing State Journal reported.

“Flint is in financial distress and will remain in receivership until I am convinced that the city is on strong financial standing,” Snyder said.

Michigan Attorney General Bill Schuette, who is expected to challenge Snyder in the 2018 gubernatorial election, said Friday he has opened an investigation into the contamination, the State Journal reported.

“While office policy generally precludes the confirmation of investigations, in this situation ... the people of Flint and throughout Michigan are rightly concerned and worried about this situation,” Schuette said.