Residents of Flint, Michigan, one of the poorest cities in the United States, will get $30 million to help pay their water bills after a lead contamination crisis, under a bill unanimously approved by the Michigan Senate on Tuesday.

Michigan Gov. Rick Snyder, a Republican, plans to sign the bill, which had been passed unanimously by the state's House last week.

"The safety and well-being of Flint families remains our top priority," said Snyder, whose administration has faced harsh criticism for its response to the contamination crisis in the city of about 100,000 residents.

As a cost-cutting measure in 2014, Flint switched its water system from Detroit to a local river. The more corrosive water from the river leached lead from water system pipes, leading to unacceptably high levels of lead in hundreds of homes.

The funding would provide Flint residents credits to cover residential water bills from April 2014 through this April or until the water is clean, Snyder's spokeswoman Laura Biehl said.

Flint residents have been using bottled, rather than tap, water because of the lead contamination. Snyder said the state will work with city leaders on how the credits are applied.

Children are especially vulnerable to lead poisoning, which could cause developmental problems.

The contamination, which could have been prevented with anti-corrosion treatment of the water, has become a political scandal as emails and documents have emerged showing that Michigan officials tried to play down and cover up the problem for months.

Snyder said in a statement that the newly approved bill would bring total emergency state funding for Flint to $70 million.

Snyder has been called to testify on the matter before a U.S. congressional committee next month. The issue has also become a focus of the U.S. presidential campaign.

Also on Tuesday, Michigan Senate Majority Leader Arlan Meekhof and House Speaker Kevin Cotter, both Republicans, announced the creation of a joint committee to review the Flint water crisis.

The committee will hear testimony on mistakes that led to this situation and explore ways to prevent such a disaster in the future, the Michigan Legislature said in a statement.