Are racial minorities sometimes disparately harmed by employers who screen potential hires for criminal records? That’s the position of the U.S. Equal Employment Opportunity Commission, but the question is still relatively untested in the courts. The EEOC itself has faced opposition from lawmakers and setbacks in background check litigation, and private plaintiffs have inked just a handful of small settlements.

Now plaintiffs can point to something more: On Tuesday, a federal judge in Manhattan green-lighted a class action on behalf of about 250,000 African-Americans who claim they were subjected to discriminatory background checks by the U.S. Census Bureau. According to Adam Klein of Outten & Golden, who represents the plaintiffs, the ruling marks the first time a judge has certified such a class in a contested case.

(Read U.S. Magistrate Judge Frank Maas’ 61-page decision here.)

Outten & Golden and a cavalcade of public interest groups have estimated that almost 854,000 of the 3.8 million applicants who sought temporary employment during the 2010 census received a form letter after their names turned up in the FBI’s criminal history database. The letter requested “official court documentation on any and all arrest(s) and/or conviction(s)” within 30 days. Based on statistics showing that African- Americans and Hispanics in the U.S. are disproportionally likely to have criminal records, the plaintiffs claim that the Census Bureau’s hiring process discriminated against black and Latino job candidates in violation of Title VII of the Civil Rights Act of 1964.

The Census Bureau, represented by counsel from the U.S. Attorney’s Office for the Southern District of New York, fought hard to defeat the plaintiffs’ bid for class action status. Among other arguments, the government lawyers cited recent U.S. Supreme Court rulings that tightened the requirements for class certification, asserting that the rejected job applicants don’t have enough in common. They also maintained that the background checks served a legitimate business purpose, and that the plaintiffs should be forced to show that the checks alone defeated their applications.

Judge Maas surveyed the bureau’s arguments and knocked down nearly all of them in Tuesday’s ruling. “The question at this preliminary stage of the litigation is not whether the challenged hiring procedures actually had a disparate impact or were justified by business necessity, but merely whether those questions can be resolved on a classwide basis,” Maas wrote.

The decision wasn’t a total win for the plaintiffs, however. While the judge certified a class to address liability and injunctive relief, he declined to certify a class on damages. The question of damages could be handled separately, Maas wrote, perhaps by a special master if the case reached that stage.

The judge also declined to include Latinos in the certified class or to certify a separate class of Latino applicants. The two Hispanic named plaintiffs didn’t score high enough on preemployment exams to be in consideration for positions, Maas ruled, though he invited the plaintiffs to amend their complaint to add new Hispanic representatives.

“The evidence will show the Census Bureau excluded many people who, on a fair review of their records, met federal standards for having no relevant criminal history,” Outten & Golden’s Klein said in a statement. Along with Klein, the plaintiffs are represented by the Center for Constitutional Rights, Community Legal Services of Philadelphia, Community Service Society of New York, the Indian Law Resource Center, LatinoJustice PRLDEF, Lawyers Committee for Civil Rights and Public Citizen Litigation Group.

A spokesperson for the Census Bureau said the agency had no comment on this week’s ruling.