For the past few weeks, the eyes of the nation have been on the city of Flint, Michigan, and for good reason.

Last month, a state of emergency was declared over the city's lead-contaminated water supply about a year after government officials switched Flint's water source to the Flint River. Many have raised concerns about the severe long-term effects of lead poisoning on youth and the delay of action and lack of transparency from the city's government has garnered criticism from politicians and advocates around the country.

However, new reports are revealing that other major U.S. cities have even higher lead exposure and more lead-affected children than Flint, and it's not just water that's the problem.

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New Jersey's Lead Problem

This week local advocacy groups found that children in 11 New Jersey cities and two counties have higher lead levels than those in Flint, according to NJ.com, a local news website. For them, the culprit is not so much through poisoned water but exposure to paint in windows, doors and other woodwork found in older homes, particularly in older, poorer cities, Elyse Pivnick, director of environmental health for Isles, Inc., a community development organization in Trenton, said in a press conference. "In light of the Flint debacle, we wanted people to understand that water is not the only thing that's poisoning children," she added. "Most people think the lead problem was solved when we took lead out of gasoline and new homes in the 1970s, but that's not true."

The cities of Irvington, East Orange, Trenton, Newark, Paterson, Plainfield, Jersey City, Elizabeth, Atlantic City, New Brunswick and Passaic, and the counties of Salem and Cumberland have the highest lead levels in the state, according to reports.

Statistics from the New Jersey Department of Health reveal that in those cities, more children had elevated lead levels in 2014 than children in Flint did in 2015.

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In 2015 alone, there were more than 3,000 children under the age of 6 in New Jersey with elevated levels of lead in their blood. Advocates estimate that about 225,000 young children in New Jersey have been affected with elevated lead levels since 2000.

However, efforts to reduce lead levels have been unsuccessful. Just weeks ago, New Jersey Gov. Chris Christie vetoed a bill that would remove lead paint from houses for the third consecutive time.

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Ever since media outlets began focusing on Flint, politicians and state advocacy groups, like the Housing and Community Development Network of New Jersey, New Jersey Citizen Action and the Anti-Poverty Network of New Jersey, have escalated their own efforts to raise awareness about the lead situation in the Garden State.

New Jersey Senator Ronald Rice told NJ.com, "We've seen the national outrage resulting from lead-contaminated water distributed in Flint. We have our own crisis in New Jersey that cannot be ignored."

Pennsylvania Has a Lead Problem, Too

In Pennsylvania, old lead-based paint is also a serious issue. The Pennsylvania Department of Health's 2014 report revealed that 18 major cities, including Pittsburgh, Philadelphia and Scranton, have rates of people with blood level rates higher than 5 micrograms per deciliter, ranging from about 8.32 to a whopping 23.11 percent. Overall, the report found that the state has a lead exposure rate of 9.37 percent.

Even more concerning is that Pennsylvania does not have a universal testing law, and so only children on medical assistance at age 1 and 2 are required by the state to be tested.

"The Department of Health is very concerned about elevated lead levels in children wherever they may occur. Our community health nurses work closely with health care providers and families every day to provide education about lead exposure and facilitate home inspections if needed to identify the source of the exposure,” health secretary Dr. Karen Murphy told CBS Pittsburgh.

Data from the 2010 Census indicates that Pennsylvania ranks third overall in the nation when it comes to houses built before 1950, which was nearly three decades before lead paint was banned. As in New Jersey, housing stock appears to be the biggest contributor to the state's lead problems.

Lead Levels Rising in Wisconsin

Michigan's neighbor has also seen a hike in lead in children. In 2014, about 4,000 children in Wisconsin were diagnosed with elevated levels of lead in their blood, according to a report from the Wisconsin Center for Investigative Journalism. The biggest pollution was found in Milwaukee, where 8.6 percent of children tested in 2014 had blood lead levels above 5 micrograms per deciliter, nearly twice the amount as in Flint. The city is where 60 percent of lead-poisoned children live, and most poisoning occurs the same way it did in Flint: through corroded lead pipes and indoor plumbing components.

Marc Edwards, the Virginia Tech professor whose team helped identify the lead problem in Flint’s water, thinks there is a huge gap in lead testing. “Neither in Flint nor in Wisconsin is the greatest at-risk group being tested,” Edwards told the Wisconsin Gazette, who featured the report. Many infants on formula may be ingesting large amounts of lead-tainted tap water but they are typically not included in standard lead testing which begins at age 1.

Many U.S. cities are not receiving as much attention as they should be for there lead-poisoning troubles, but there could be a upside: Learning more about water supply issues from Flint, New Jersey, Pennsylvania and Wisconsin could inspire much needed action around the country.