By Timothy Mclaughlin

(Reuters) - Infants and toddlers in Michigan should undergo mandatory lead screening, a panel of experts said on Thursday, as the Midwestern state continues to grapple with the ongoing effects of a lead crisis linked to contaminated water in the city of Flint.

The Child Lead Poisoning Elimination Board, created in May by Michigan Governor Rick Snyder, said that required screening for exposure to the toxic metal would help fill gaps in treatment and prevention that occur under the current targeted blood screening recommendations.

"Because we are not screening all children, we don't know how big of a problem it is and we don't know where these (exposure) hot spots are," Dr. Mona Hanna-Attisha, director of the Pediatric Residency Program at Hurley Medical Center in Flint and a member of the board, said at a news conference.

The report recommends children be tested at the ages of 9-12 months and again at 24-36 months. This testing would help to identify high-risk areas that would then be subject to more comprehensive remediation efforts.

The Roadmap to Eliminating Child Lead Exposure also recommends environmental lead testing as part of a primary prevention program and building a database of homes that have increased levels of lead.

"Right now we are essentially, as a state, intervening after a child has been lead poisoned," said Lyke Thompson, a board member. "We need to turn that around and make sure we get ahead of the problem."

Michigan has been at the center of a public health crisis since last year, when tests found high levels of lead in blood samples taken from children in Flint.

The lead exposure was linked to an April 2014 decision by a state-appointed emergency manager to switch Flint's water source to the Flint River from Lake Huron to save money. The more corrosive river water caused lead to leach from city pipes and into the drinking water.

The predominantly black city of 100,000 switched back in October 2015, but the water has not fully returned to normal. Flint has been replacing lead pipes running to homes, and state officials have said the water is safe to drink if properly filtered.

Last week, a federal judge ordered state and city officials to deliver bottled water directly to qualified residents in Flint.

On Thursday, the state filed a motion to block the order, saying it "far exceeds what is necessary to ensure Flint residents have access to safe drinking water."

(Reporting by Timothy Mclaughlin in Chicago; Editing by Alan Crosby and Dan Grebler)