Disability advocates say that federal education officials acted illegally by fundamentally altering the way they handle discrimination complaints in schools.

A lawsuit filed this week accuses the U.S. Department of Education of skirting its obligation to investigate complaints of disability and race-based discrimination in the nation’s schools.

The legal action comes after the Education Department issued an updated manual in March allowing the agency’s Office for Civil Rights to dismiss complaints that are “a continuation of a pattern of complaints previously filed with OCR by an individual or group against multiple recipients, or a complaint is filed for the first time … that places an unreasonable burden on OCR’s resources.”

Moreover, the new guidelines prevent complainants from appealing if their case is dismissed.

The changes came without any public notice or opportunity for comment, steps required under the federal Administrative Procedure Act, according to the lawsuit filed in U.S. District Court in Maryland by the National Federation of the Blind, the Council of Parent Attorneys and Advocates and the National Association for the Advancement of Colored People.

“The changes to the manual are contrary to OCR’s mission … and, in effect have summarily eliminated substantive rights of the very people OCR purports to serve,” said Denise Marshall, executive director of the Council of Parent Attorneys and Advocates. “With this arbitrary and capricious action OCR has abandoned its basic duty to investigate legitimate complaints of discrimination by students with disabilities and their parents.”

In addition to the Education Department, Secretary of Education Betsy DeVos and Candice Jackson, the agency’s acting assistant secretary for civil rights, are named in the suit which asks the court to deem parts of the agency’s new manual invalid and prohibit implementation.

Elizabeth Hill, a spokeswoman for the Education Department, said she couldn’t comment on pending litigation, but indicated that the manual update does not change the Office for Civil Rights’ “commitment to robustly investigating and correcting civil rights issues.”

“The new case processing manual now says that OCR will dismiss complaints if they’re part of a pattern of similar complaints filed by an individual or a group. This provision is intended to permit OCR to remain active in every type of discrimination subject matter while retaining discretion to engage in technical assistance efforts where appropriate,” Hill said.