WASHINGTON/CHICAGO: The head of the Midwest region of the US Environmental Protection Agency offered her resignation over the water contamination crisis in Flint, Michigan, the agency said on Thursday, as it issued an emergency order to resolve the growing problem.

Susan Hedman, the second official to resign since the crisis unfolded, had played down a memo by an EPA employee that said tests had shown high levels of lead in the city’s water, telling Flint and Michigan administrators it was only a draft report.

Hedman’s resignation will take effect Feb. 1, the EPA said. Before the agency’s announcement on Hedman, the White House said President Barack Obama will ensure officials will be held accountable if any wrongdoing is found.

The EPA on Thursday issued an emergency order requiring Michigan and the city of Flint to take immediate steps after determining that their response to the crisis had been “inadequate to protect human health.”

Under the direction of a state-appointed emergency manager, Flint, a working class mostly African-American city of 100,000 north of Detroit, switched water supplies to the Flint River in 2014, to save money. The river is known locally as a dumping ground.

The more corrosive river water, which was not treated, caused more lead to leach from the city’s aging water pipes than the Detroit water the city had tapped previously.

Complaints about the water began within a month of the change, but officials did not take steps to remedy the situation until October 2015 after tests showed elevated levels of lead in some tap water in the city and in some children. Lead is a neurotoxin that can damage brains and cause other health problems.

The city switched back to Detroit water in mid October, but the contamination continued.

The Flint crisis pushed EPA Administrator Gina McCarthy on Thursday to issue a new policy to elevate any issues that appear to be a substantial threat to public health, or that “other authorities appear to be unable to address.”

“Our strength can become a weakness if we interpret our responsibility as ending with simple technical compliance,” McCarthy said in a memo to all EPA staff.

The EPA’s inspector general agreed to evaluate the Midwest office’s public water system supervision program and its implementation of its state oversight.

Representative Jason Chaffetz, chairman of the House Oversight and Government Reform Committee, said “The EPA is rife with incompetence and Region 5 is no exception. Mismanagement has plagued the region for far too long and Ms. Hedman’s resignation is way overdue.”