WASHINGTON — A group of minority firefighter applicants won a Supreme Court appeal Monday over whether they waited too late to file a workplace discrimination lawsuit.

The justices unanimously decided the Chicago city applicants can collect damages as part of a class action on behalf of thousands of fellow African-Americans.

At issue was a filing deadline for complaining to federal officials about the use of an employment test that has a stronger negative impact on minority applicants. The court concluded the time to file a charge with the Equal Employment Opportunity Commission began when the results were used to make actual hiring decisions. The city claimed the clock started to run when the initial test results were released.

The high court ruling came a year after a highly contentious but separate dispute also involving firefighters. In that 5-4 decision, the justices ruled New Haven, Conn., officials violated the civil rights of white workers when a promotion test was thrown out after no Black firefighters scored high enough to advance.

The Chicago case began in July 1995, when officials administered a written test for more than 26,000 applicants to serve in the city’s fire department. Those who scored 89 or above were considered “well qualified,” and had a much easier path to being hired. Those below 65 (on a 100-point scale) had failed and were no longer considered.

The middle-range applicants — who scored between 65 and 88 — were considered “qualified” but were told they were not likely to be hired because so many others had received 89 or more on the test. Most of those in the “well-qualified” category were white. Only 11 percent were Black.

After several hiring rounds in which only well-qualified applicants were chosen, the city in the 11th round filled the remaining slots with “qualified” candidates instead.

Crawford Smith was among six African-American applicants who first sued in 1998. He had scored in the “qualified” range but was never contacted for an entry-level job as a candidate firefighter. On behalf of the more than 6,000 African-Americans who scored in the qualified range, the Black applicants claimed the 89-point cutoff created a “disparate impact” against them, and against a diverse workforce.

Federal law requires those bringing suit to do so within 300 days of an alleged “unlawful employment practice.” The city said the clock began when the first test results were announced in January 1996. The first lawsuit was filed 430 days later.

But the plaintiffs in their lawsuit claimed a completely new act of discrimination occurred every time a new round of hiring took place — using the original test results — between 1996 and 2001.

A federal judge eventually agreed, and ordered the hiring of 132 randomly selected Black applicants who scored in the “qualified” or above range. A federal appeals court then overturned that ruling.

The high court now has reversed that ruling.

“It does not follow that no new violation occurred — and no new claims could arise — when the city implemented that decision down the road” to adopt the cutoff score for its hiring, said Justice Antonin Scalia. “If petitioners could prove the city used the practice that causes a disparate impact, they could prevail.”

The city argued during oral arguments before the justices in February that its hiring practices have been in place for years, relying on an long-accepted test-score range, and that any discrimination was unintended. They said a ruling against them could lead to a flood of lawsuits from workers claiming discrimination going back many years.

But Scalia said that is a matter for the legislature, not the courts, to decide.

“It is not our task to assess the consequences of each approach and adopt the one that produces the least mischief. Our charge is to give effect to the law Congress enacted,” he said. “Congress allowed claims to be brought against an employer who uses a practice that causes disparate impact, whatever the employer’s motive and whether or not he has employed the same practice in the past. If that effect was unintended, it is a problem for Congress, not one that federal courts can fix.”

Civil rights groups hailed the high court decision.

“Today, the Supreme Court affirmed that job-seekers should not be denied justice based on a technicality,” said John Payton, president of the NAACP Legal Defense and Educational Fund, and the lawyer who argued the case before the justices. “This victory goes well beyond the immediate results in Chicago. It should ensure that no other fire department or employer uses a discriminatory test, and LDF will go the extra mile to make sure that they do not.”

The separate New Haven case had been a major source of contention during Justice Sonia Sotomayor’s confirmation hearings for the high court last year. She had ruled against the white firefighters in their discrimination claim when she sat on a New York-based federal appeals court.

The justices in that appeal reversed, finding “the city rejected the test results solely because the higher scoring candidates were white.”

Justice Anthony Kennedy, writing for the conservative majority, added, “Confronted with arguments both for and against certifying the test results — and threats of a lawsuit either the way — the city was required to make a difficult inquiry. But its hearings produced no strong evidence of a disparate-impact violation, and the city was not entitled to disregard the tests based solely on the racial disparity in the results.”

Four more liberal justices argued the decision would do untold damage to the promotion of equal opportunity.

The latest case is Lewis v. Chicago (08-974).