The U.S. Department of Justice (DOJ) filed a lawsuit last week against the State of Michigan and its Department of Corrections, following through on a February notice from the federal agency.

The lawsuit, filed on June 13 in a Michigan district court, alleges that female correctional officers at the Women’s Huron Valley Correctional Facility in Ypsilanti have been forced to work unfair overtime shifts and have been denied transfers and promotions. Huron Valley is the state’s only prison for women.

The DOJ said in a statement that the allegations constituted a pattern or practice of violations related to Title VII of the Civil Rights Act of 1964. The landmark legislation prohibits discrimination in employment on the basis of race, color, sex, national origin, or religion, and was last amended in 2009.

Michigan officials specifically discriminated against its women employees by implementing an “overly broad female-only assignment policy” and by denying their repeated requests for transfers, according to the 19-page lawsuit.

The lawsuit filed last Monday revealed that 28 former and current correctional officers had filed charges in 2010 and 2011 with the Equal Employment Opportunity Commission (EEOC) to challenge the state’s policies. After investigating the charges and finding reasonable cause that Michigan had committed Title VII violations, the EEOC sought conciliation to no avail. It ultimately referred the charges to the DOJ.

“Qualified male and female correctional officers deserve equal opportunities to compete for job assignments and transfers without unnecessary barriers,” said Vanita Gupta, the head of the DOJ’s Civil Rights Division and the principal deputy assistant attorney general, in the statement.

Michigan Corrections Department spokesperson Chris Gautz told Rewire the department did not have a statement at the time and that it typically does not comment on pending litigation. Representatives from Republican Gov. Rick Snyder’s office did not respond to an email from Rewire on Friday.

The complaint alleges that the corrections department began its discriminatory practices in 2009, just a year after it consolidated its three adult female correctional facilities into one location. That year, the state designated 11 positions at Huron Valley as “female-only,” including food service, yard control, property room, and electronic monitor officer positions.

According to the lawsuit, Michigan officials only lifted the “female-only” restrictions on some of the positions earlier this month. And two months prior, in April 2016, the state offered a limited transfer opportunity to five women correctional officers, but that did not change an existing transfer freeze that has kept several women officers from being promoted or moved to facilities closer to their homes.

Despite the transfer freeze, several eligible male officers in the last six years have been allowed to move to other facilities throughout the state, while women officers were forced to stay in old positions and work consecutive overtime shifts, the suit claims.

Huron Valley, the overcrowding challenges of which were publicized by the Detroit Free Press in 2015, has about 2,200 inmates and a 85 percent female-majority correctional officer staff, according to the lawsuit. In 2012, the U.S. Government Accountability Office (GAO) published a study about overcrowding at federal prisons, concluding that correctional institutions that are over capacity have a negative effect on inmates, staff, and infrastructure.

The report noted that inmates in particular were more likely to experience factors leading to increased inmate misconduct, comprising the safety and security of other inmates. Others studies, such as 2007 research from the Clinical Infectious Diseases journal, noted that people in prisons are at a higher risk for acquiring blood-borne pathogens, sexually transmitted infections, and methicillin-resistant Staphylococcus aureus infections, and that overcrowding only exacerbates the problem.

Former Huron Valley correctional officer Latasha Clements, in an email obtained by the Detroit Free Press, wrote to prison, union, and legislative leaders that the facility’s mandatory overtime shifts—caused by its shortage of female corrections officers—had led her to quit her job.

The email included the statement that “constant mandating, three and four days consecutively” had caused her physical and emotional health to deteriorate, and negatively affected her ability to adequately care for her husband and children.

The former state prison worker was one of a dozen Huron Valley corrections officers who quit their jobs in the last six months, according to the Detroit Free Press report.

The DOJ lawsuit demands a jury trial and a court order requiring Michigan to end discriminatory job assignment and transfer policies. The DOJ has also requested monetary damages for the affected correctional officers, and an order for the state to develop and implement lawful and effective measures to prevent further discrimination.

Barbara L. McQuade, the U.S. attorney for the Eastern District of Michigan, said in an official statement that the lawsuit does not challenge “positions where it makes sense to assign only female officers,” but rather the practice of limiting “positions that are not justifiably related to inmate privacy to women officers.”

The DOJ lawsuit is not the first legal act the federal government has brought against the State of Michigan. In 1997, the United States sued Michigan under the Civil Rights of Institutionalized Persons Act for violating the constitutional rights of women inmates by not protecting them from sexual misconduct and unlawful invasions of privacy.