Residents in Newark, New Jersey, are facing a growing emergency over lead contamination in the city’s drinking water supply.

The crisis is the result of years of mismanagement and has forced city officials to warn tens of thousands of residents against drinking tap water for fear of lead poisoning.

Here’s what you need to know:

When The Crisis Began

Newark has been struggling to curb elevated levels of lead in its drinking water supply for years. The Newark Board of Education has consistently found elevated lead levels in water at city schools since the 2010-11 school year.

The board responded by turning off or fixing fountains found to have elevated lead levels and installing new “lead-free” water lines and fixtures. But the problem persisted.

Officials in 2017 found that more than 10% of homes across Newark had nearly twice the amount of lead in their drinking water that the U.S. Environmental Protection Agency considers the threshold for taking action.

Officials have handed out over 38,000 lead-safe water filters to residents since 2018 and installed a new corrosion control treatment system in May.

But a recent round of tests showed lead levels in the drinking water sampled still exceeded 15 parts per billion, the EPA threshold.

This week, city officials said the elevated levels were “due to the releasing of lead from plumbing and lead service lines on private property between the street and approximately 15,000 homes.” The city also said a major water treatment plant’s corrosion control system “became less effective at reducing the corrosion of lead pipes and resulted in rising lead levels in some homes with lead service lines throughout Newark.”

Who The Crisis Is Affecting

Many of the affected neighborhoods are predominantly Black and lower-income.

“It’s a right, not a privilege, to have clean, safe water and we are committed to that,” New Jersey Gov. Phil Murphy (D) said on Wednesday.

New Jersey Sen. Cory Booker (D), who formerly served as Newark’s mayor and is now a Democratic presidential candidate, also noted the racial imbalance in who was suffering from the crisis.

“Newark’s water emergency demands our federal government’s immediate attention. Everyone deserves clean, safe water - it’s shameful that our national crisis of lead-contaminated water disproportionately hits poor black and brown communities like my own,” he wrote in a tweet on Wednesday.