Updated 07/16/13 – 11:29 a.m.

CHICAGO (CBS) — A federal judge has begun a hearing on two lawsuits seeking to block plans to close 49 elementary schools, with testimony expected to last for up to four days.

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One of the lawsuits seeks a permanent injunction blocking the school closings; the other asks for a delay of at least a year before the closings can be carried out.

U.S. District Judge John Lee has set aside four days to hear from officials at the Chicago Public Schools, and parents who oppose the district’s school closings plan.

The Chicago Teachers Union filed two federal lawsuits in May, on behalf of parents at schools affected by the plan, arguing the closings will inordinately affect students in African-American neighborhoods.

The first witness, Dr. Pauline Lipman, professor of Educational Policy Studies at the University of Illinois at Chicago, said 87 percent of the students affected by the closings are black, but only 40 percent of all students in CPS are black.

The plaintiffs also claimed the district failed to set up a sufficient process for disabled and special needs students to adjust to their new schools.

CTU Financial Secretary and special education teacher Kristine Mayle claimed proper preparations have not been made to get students with special needs and other disabilities ready to attend their new schools.

After court, Mayle said if the lawsuits fail to stop school closings, “Kids are gonna die. Point blank, kids are gonna die.”

“They have kids crossing gang boundaries. My students with learning disabilities, and other disabilities – that they’re not aware of social cues – are going to be sent into an unfamiliar neighborhood with unfamiliar kids, and they don’t know how to protect themselves,” she said.

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The district has said the buildings set to close were underused, and shifting students from those locations to new schools will save millions of dollars at a time CPS is facing a projected $1 billion deficit.

CPS has asked the judge to dismiss the lawsuits.

Lipman testified there’s not a lot of research on the effect of school closings, because it’s a fairly new tactic for school officials anywhere.

However, she said the research that has been done shows closing schools harms students. Relocating students can affect them emotionally, socially, and academically, she said.

In many cases, schools were students are relocated are only marginally better – if at all – than the schools that were closed.

An attorney for the Chicago Board of Education asked if Lipman knew about plans to improve education at the so-called “welcoming schools.” Lipman said she was aware of what CPS has promised, but hasn’t seen those programs in place.

A ruling on the two federal lawsuits is not expected right away after the hearing concludes later this week. Classes resume for Chicago’s schools on Aug. 26, and the district has begun shuttering many of the schools on the closing list.

The teachers union has filed a third lawsuit in Cook County Circuit Court, seeking to stop closings at 10 elementary schools. That lawsuit claims the district did not follow proper procedures in closing 10 schools, and should have followed recommendations from independent hearing officers to keep them open.

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The district also is seeking to dismiss that case.