LANSING, Mich. (AP) — Plaintiffs in a landmark legal settlement related to Flint's lead-tainted water have asked a federal judge to intervene because they say city officials have repeatedly ignored requirements that allow monitoring of whether the court-ordered deal is being followed.

The motion, filed late Wednesday in federal court in Detroit, accuses Flint and its city administrator of a "pattern of nonresponsiveness, delay and noncompliance" with providing status updates and other information. The agreement, which was approved in March, requires the city to dig at 18,000 Flint households and replace their underground water lines if they are made of lead or galvanized steel.

Other requirements include tracking which residents refuse to let their pipes be replaced, making periodic visits to homes to install and maintain faucet filters, and responding to additional information requests. Federal and state governments are covering the bill.

"The city's violations are not merely procedural or formalistic. They frustrate the very purpose of the agreement by impeding plaintiffs' ability to monitor and enforce its other terms," lawyers for the Natural Resources Defense Council and American Civil Liberties Union of Michigan wrote. The other plaintiffs listed in the motion are the group Concerned Pastors for Social Action and Flint resident Melissa Mays.

In a statement Thursday, Flint Mayor Karen Weaver defended her administration while saying the motion deals only with proposed changes to how status reports are provided and does not jeopardize pipe replacements.

City employees "have been focused, first and foremost, on the effort to replace lead-tainted pipes leading to residents' homes," she said. "They have made it a priority to get contractors and residents what they need to ensure the progress and productivity of that effort."

The plaintiffs contend that without the disclosures, they cannot verify if the city is replacing service lines "in a comprehensive and health-protective way" or if it is adequately coordinating with the state to ensure all residents have properly installed filters that remove lead. They are not seeking contempt sanctions or civil penalties, but want U.S. District Judge David Lawson to oversee a more extensive reporting and certification process and to order the city to file future status reports with the court.

The motion is a "last resort," according to the filing, and comes after nine months of the city providing "late, incomplete and inaccurate" status reports. Weaver countered that Flint "has worked collaboratively" to adhere to reporting requirements.

"No one wants to get the lead out of Flint more than me," she said.

Weaver said pipes to more than 6,229 homes have been replaced since 2016. The goal is to replace nearly 20,000 service lines by 2020.

Flint ran into extraordinary trouble when emergency managers appointed by Gov. Rick Snyder put the city on water from the Flint River in 2014 while a pipeline was being built to Lake Huron. The corrosive water was not properly treated due to an incorrect reading of federal regulations by state regulators, and lead leached from old plumbing into homes and led to elevated levels of the toxin in children.

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