Older workers can sue their employers for age discrimination, even if the resulting harm is not deliberate, the Supreme Court ruled Wednesday.

The highest federal court voted 5-to-3 that the 1966 Age Discrimination in Employment Act allows such lawsuits. But people who sue must have a high threshold of evidence. The law covers an estimated 75 million working people age 40 or older.

The ruling sided with the plaintiffs – 30 older police officers in Jackson, MS – who alleged that new wage scales established by the city were unfair to older workers. The court said the workers did not have to prove the city deliberately tried to discriminate.

Good faith by employers “does not redeem employment procedures or testing mechanisms that operate as ‘built-in headwinds’ for minority groups and are unrelated to measuring job capability,” wrote Justice John Paul Stevens and four other justices in the majority opinion.

Even though the Supreme Court agreed with the officers’ right to sue, it dismissed their suit, saying the officers did not prove that the city’s policies disproportionately harmed them.