As winter-weary Minnesotans crack open their windows each spring, Twin Cities health officials see a jump in the number of cases of lead-poisoned children.

That's because old windows coated in lead paint are the primary cause of childhood lead poisoning in the metro area. Toxic paint dust flies every time windows are opened, landing on floors and household surfaces and ending up in the mouths of crawling tots and curious kids.

"With Flint, Michigan, everyone is so paranoid about lead in water. Yet we hardly ever have a child that's been lead poisoned by water," said Jim Yannarelly, Ramsey County Healthy Homes supervisor. "In Minnesota and the Twin Cities, it's windows, windows, windows."

That's why Ramsey and Hennepin counties and Minneapolis have helped replace windows with lead paint in nearly 7,200 homes since the early 1990s. They've split millions in U.S. Department of Housing and Urban Development (HUD) grants to pay for the programs. The funding has helped families fix their homes when a child is diagnosed with high lead levels and also provided resources to change out windows before poisoning occurs.

"The HUD grants over the last 20 years have been a huge boon. We would not be where we are now" without them, said Lisa Smestad, Minneapolis' healthy homes and lead hazard control manager.

The number of confirmed cases of elevated childhood lead levels in Minnesota, using the Centers for Disease Control and Prevention (CDC) standard of 5 micrograms per deciliter, declined by nearly 30% from 2012 to 2017.

Cases in Minneapolis dropped from more than 500 in 2008 to 90 last year, and Ramsey County reported a similar decline.

But health department officials say it likely will take several more decades before the danger is gone. Congress banned lead in paint in 1978, but inspectors still find it in older homes across the metro area.

"People are surprised. They say, 'Didn't we get rid of lead in paint?' " Smestad said. "But in Minneapolis, 75 percent of residential properties were built before lead paint was banned."

Older Minneapolis neighborhoods, including the North Side, Phillips and Powderhorn, are hot spots. Across the river, inspectors often find lead paint in older homes on St. Paul's East Side.

"Lead paint is such a durable paint. That's why we painted it on window jams, window sashes and front porches," Yannarelly said.

Figuring out the hazard

Early childhood exposure to lead can lead to lifelong neurological and learning deficits, and the kind of impulse-control problems that can involve law enforcement. There is no safe blood lead level in children, according to the CDC.

"Even at low levels, there can be permanent neurological damage, learning disabilities and behavior issues," said Mike Jensen, supervisor of Hennepin County's lead hazard control program.

In Minnesota, family doctors order blood tests during pediatric checkups that measure lead levels; about 81% of children born in the state after 2014 have been screened for lead. Those results are reported to the Minnesota Department of Health, which either investigates directly or transfers cases of lead poisoning and elevated lead levels to larger local health departments.

Local officials work with residents and landlords to determine the cause of the poisoning and ways to remedy it.

Health departments write corrective orders and can levy fines. In extreme cases involving rental properties, they can go after rental licenses.

"Most parents are really concerned about their children," Smestad said. "They want us to figure out the hazard so they can move it away from the children."

In Minneapolis, health inspectors go to a home, diagram the living quarters and then use a handheld x-ray fluorescent device to measure lead levels in nearly every painted and varnished surface: windows, walls, baseboards, doors, floor and porches. A public health nurse and an environmental health specialist do a similar inspection in Ramsey County.

"A lot of people don't think about varnish, but in old houses they put lead in the varnish. They even put lead in the ceramic tubs," Smestad said. "Like asbestos, they threw it into everything."

Grateful for the help

Once lead paint is found, the health department identifies temporary and long-term fixes. A new coat of paint can seal the lead paint in some cases, but that isn't often a good solution for "friction" surfaces including windows.

Smestad said they also warn families planning remodeling projects to take precautions, especially when sanding older surfaces. An entire family fell ill after the parents sanded the deck on an older home.

"They thought the whole family had the flu. Actually, the whole family was lead-poisoned," she said.

Childhood lead poisoning often occurs in older houses and apartments in lower-income areas, where families can least afford to make the fixes, Yannarelly said.

"Windows are one of the most expensive repairs you can do," he said. "People are more worried about the next meal, paying the rent."

Each local department offers varying level of assistance based on income and whether the home is owned or rented. But all of them target homes with children under the age of 6.

May Vang, a retired grandmother in Brooklyn Center, got her windows replaced last winter with the help of the Hennepin County program.

Vang, 70, has a dozen grandchildren, including four toddlers and an 8-month-old she babysits during the week at her home. Toddler toys are neatly lined up along the wall of her living room.

When neighbors told her that they had windows with lead paint, Vang had her windows checked and found that they too were coated in toxic paint. She was grateful for the county program because her grandkids spend most of their time in the living room with its large picture windows.

"Every time I look up they are running to the window," she said. "I wanted to get it safe for them."

Out of an abundance of caution, Vang also had her grandchildren's blood tested. "They don't have any lead in their blood," she said.

Now, she's talking to her friends and neighbors about the risks that windows pose to children and the program that can help. "I am so glad we have the problem fixed," she said.