A Department of Justice investigation has found that only 17 percent of New York City elementary schools are fully compliant with the Americans with Disabilities Act. The two-year investigation also found that six school districts in New York City lacked a single elementary school that was considered "fully accessible" under the law.

U.S. Attorney Preet Bharara sent the findings to the city's education department in the form of a 14-page letter on Monday, detailing the city's violation of federal law.

"Our investigation revealed that, 25 years after the passage of the Americans with Disabilities Act, the city is still not fully compliant, and children with disabilities and their families are being denied the right to equal access to a public school education," Bharara said in a statement. 

Violations included a lack of ramps and elevators; doors that required too much force to open; improper signage, such as exterior signs that did not have raised characters; and main office counters that were too high.

The investigation also found that when school officials made upgrades to school buildings, the city still failed to consistently comply with the law. In one egregious example, Bharara pointed to a school in Queens that installed an elevator, but did not make the elevator accessible to people with disabilities.

“Our goal is to ensure that all our students have access to a high-quality education; and a student’s disability should never get in the way of their access to a great school," said Harry Hartfield, a spokesman for the city's education department. "We are reviewing the United States Attorney’s letter and remain committed to increasing the accessibility of our school buildings.”

Lori Podvesker, manager of disability and education policy for the advocacy organization INCLUDEnyc, said she was pleased to have a spotlight put on an issue well-known to disability rights advocates.

"It’s not just the students being blocked," said Podvesker. "It’s parents. It's teachers who can only work in certain schools."

Voters could be blocked on Election Day too, she said, since schools are often polling sites.

The school system needs an independent monitor to hold the Department of Education accountable for complying with the law, Podvesker said, adding that the city must also do a better job of making sure parents know they have the right to ask for accommodations for their child.