While the contaminated water crisis in Flint, Michigan, has been unfolding for more than a year, the scandal is finally breaking through to the national stage after two leading Democratic presidential candidates discussed the public health emergency at Sunday's debate.
For those who haven't been following, below is everything you need to know about the who, what, where and whys surrounding the Flint water crisis.
What's happening?
A Michigan city is facing the fallout of a public health crisis that poisoned its water supply for more than a year, leading to increased levels of lead in children's blood. Some believe the spike may be linked to a recent outbreak of severe pneumonia, known as Legionnaire's disease.
The Legionnaire's outbreak has left at least 87 people sick — and 10 dead — since 2014, when the city temporarily switched to a new water supply to save money.
Where is Flint?
With just under 100,000 residents, Flint, located about 66 miles northwest of Detroit, serves as the county seat of Genesee County.
Census data shows the city is predominantly black (55%), with 40% of all residents living below the poverty line.
Critics of the state's response have called the crisis a "civil rights issue."
"We would be outraged if this happened to white kids," Democratic presidential candidate Hillary Clinton said during a speech on Monday. "And we should be outraged that it’s happening right now to black kids."
How did this happen?
The current crisis flows from a decision, in 2014, to temporarily source the city's water from the nearby Flint River.
In 2013, the City Council decided to save $5 million by abandoning the city's longtime arrangement with Detroit to purchase water sourced from Lake Huron. The city would connect to a new pipeline to deliver water directly from the lake, but with that pipeline still under construction, officials needed another source of water — the Flint River — in the meantime.
There is no record of the City Council voting to specifically use the Flint River as the short-term solution, according to MLive.com, but a state-appointed emergency manager who oversaw the switch to that water source blames the decision on the council. City officials, conversely, are pointing the finger at Darnell Earley, the emergency manager, who came to power seven months after that initial 2013 decision.
After the switch, residents almost immediately began to complain about the water's taste and appearance. Others reported symptoms, including rashes and hair loss, but local officials insisted that the water was safe.
A group of researchers at Virginia Tech eventually decided to study the water and, in September 2015, concluded that it was "creating a public health threat." The river water, they found, was more corrosive than Lake Huron's water, which damaged older pipes and allowed iron and lead to enter the city's water supply.
More evidence piled up in late September, when Mona Hanna-Attisha, a local pediatrician, analyzed patient data and found that the number of Flint children with elevated levels of lead in their blood nearly doubled — from 2.1% to 4% — since the city changed its water supply, the Detroit Free Press reported.
A week later, state health officials reanalyzed their own data and confirmed Hanna-Attisha's findings while county officials declared a public health emergency and the city switched back to buying water from Detroit. President Barack Obama declared a federal state of emergency in Flint a few days ago.
Officials revealed an even more disturbing finding this month, when they revealed that since June 2014, there have been 87 cases of Legionnaires' disease in Genesee County, including 10 that resulted in death.
Who's responsible?
The failures in Flint have involved officials from every level of government.
In the fall, state officials from the Michigan Department of Environmental Quality admitted it failed to follow federal rules for corrosion prevention, eventually prompting a class-action lawsuit from the American Civil Liberties Union and DEQ Director Dan Wyant's resignation in December.
The state's attorney general
And while Gov. Rick Snyder has apologized and recently deployed the state's National Guard to help distribute bottled water and filters, his slow response has earned strong criticism.
Over the weekend, Democratic presidential candidate and Vermont Sen. Bernie Sanders took Snyder to task and called for his resignation.
Sanders Statement: Michigan Governor Must Resign over Flint Lead-Poisoning Crisis pic.twitter.com/6hDPRg5iWw— Bernie Sanders (@BernieSanders) January 16, 2016
"The governor long ago knew about the lead in Flint's water," Sanders said in a statement. "Thousands may have been exposed to potential brain damage from lead. Gov. Snyder should resign."
CORRECTION: The Legionnaire's outbreak that has sickened 87 people and killed 10 began in June 2014, not 2004.