Every day cars, trucks, and semi-trailers stop in front of St. Mary's Church in Flint, Michigan, some coming from nearby towns and others from as far off as Cleveland and Chicago. But all of the vehicles carry the same precious cargo: clean water.

And every day church volunteers unload the trucks and go door-to-door distributing donated bottles and jugs to the citizens whose tap water was turned toxic by a combination of lead contamination and government mismanagement.

"They live in the United States of America and they deserve clean water," said St. Mary's bookkeeper Kathleen Tomczyk. "That's a God-given thing and we need to stop blaming people and we need to fix it."

A fix that will see clean, safe water running out of every tap in Flint remains illusive. But Congress is poised to begin its examination of who is responsible for the poison leaching out of the city's pipes and into the water supply, with a hearing before the House Committee on Oversight and Government Reform taking place on Wednesday.

But they'll be missing at least three key figures at the center of the crisis: Michigan's Republican governor, the emergency manager he appointed to deal with Flint's fiscal woes, and Miguel Del Toral, the Environmental Protection Agency (EPA) scientist who raised concerns that Flint's water testing could be flawed and the lead contamination widespread.

The hearing comes at the request of Rep. Brenda Lawrence. The Michigan Democrat said she wants to hear about why Flint's mostly African-American population of 100,000 was exposed to lead-contaminated water.

State-appointed Emergency Manager Darnell Earley is facing particular scrutiny because he decided to switch the city's water source from Lake Huron to the Flint River in 2014 in order to cut costs. Residents soon saw their tap water turn yellowish brown. But for much of the the next year and a half, federal, state, and local officials downplayed the health concerns — despite some having knowledge of the contamination.

Exposure to lead can cause irreversible brain damage, especially among children.

The first person appearing before the committee tomorrow will be Congressman Dan Kildee, a Democrat who represents Flint. He said the crisis is the result of bad decisions made by state officials, especially Michigan Governor Rick Snyder.

"The State of Michigan did this to Flint," Rep. Kildee said. "It was a combination of the emergency manager, appointed by the governor, looking at nothing but cost when determining how to provide water to the people of Flint and then the Michigan Department of Environmental Quality, not only failing to protect public health, but actually covering up the fact that they failed."

Kildee said it is important that the state's role be made clear, not so blame can be assigned, but because national attention is needed to see the problem solved. But he also expressed concern that neither Gov. Snyder nor Earley will appear at the hearing.

Snyder was not asked to appear before the committee and Earley is refusing to attend.

In his State of the State speech last month, the governor issued a sweeping apology to the people of Flint and pledged full transparency going forward.

"I'm sorry, and I will fix it," Snyder said. "You deserve accountability. You deserve to know that the buck stops here with me. Most of all, you deserve to know the truth, and I have a responsibility to tell the truth."

Scheduled to appear before the committee are Joel Beauvais, acting deputy assistant administrator of the Office of Water at the EPA; LeeAnne Walters, a Flint resident; director of Michigan's Department of Environmental Quality Keith Creagh; and Marc Edwards, the Virginia Tech University professor, who first detected the contamination and is now overseeing water testing for the city.

In a memo, the House committee said it expects to focus on the role of the federal government in the Flint disaster, likely including that of former EPA administrator Susan Hedman, who resigning last month amidst the crisis.

But national and Michigan Democrats are furious that the largely Republican committee will not be questioning Gov. Snyder, also a Republican, nor Earley.

"I am deeply disappointed at the Majority's lack of commitment to a thorough and meaningful hearing," said Rep. Lawrence in a statement last month. "The nearly 100,000 people of Flint who have been permanently impacted by this crisis, either directly or indirectly, demand that Congress set aside party politics if we are to ensure that this never again occurs in Flint or any city in America."

The House Energy and Commerce Committee is investigating EPA's role in the water crisis. And state and federal agencies, including the Federal Bureau of Investigation, are pursuing possible criminal charges.

But for the people at St. Mary's Church and the many other community groups helping distribute water in Flint, the pursuit of justice is a secondary matter. Their priority is just getting people the clean water they need to cook, bathe, and drink."I know eventually the free water from all over is going to die down," said Tomczyk. "But we're still going to have to give them water, because it's not going to be an easy fix. It's long range."