Roughly 1,000 public school teachers in Washington, DC, are operating without a license, according to a report released Thursday.

The report from NBC 4 Washington found that about one in four teachers in D.C. Public Schools taught without a license during the 2017-2018 school year.

The news station analyzed D.C. Public Schools and Office of the State Superintendent of Education (OSSE) databases of new and veteran teachers over the past year, many of them obtained through Freedom of Information Act (FOIA) requests.

There are also at least four teachers who hold top advisory positions in the Chancellor’s Teacher’s Cabinet, which meets with the chancellor of D.C. public schools and doles out policy advice to top officials within the school district.

Ahnna Smith, D.C.’s deputy mayor for education, said the school district is violating D.C. regulations and is putting itself in danger of losing U.S. Department of Education grant money.

Despite the claims, D.C.’s public school system says it conducts background checks on anyone who applies for a position.

“Licensure requirements exist for a reason. It doesn’t make a lot of sense that the District hasn’t embraced a good credentialing system,” said Gaston de los Reyes, father of two students at Oyster-Adams Bilingual School.

It is unclear how many of those unlicensed teachers participate in Teach for America, a program where many recent college graduates teach without a traditional license in underserved school districts for a year before obtaining their teaching certification.

The organization, which supports illegal immigrants who stay in the country under the Deferred Action for Childhood Arrivals (DACA) program, states on its website that it can send DACA recipients to teach in the D.C. public school system and other urban school districts across the U.S.

Denver Public Schools also sought out unlicensed educators, specifically those with DACA status, to teach in the school system back in 2014.