An almost 15-year-old age discrimination class action against the Occupational Safety and Health Administration has been revived after having been certified and decertified over the years.

More than 1,400 people are eligible class members, according to the case attorney. If the class is successful, current and former OSHA workers could receive decades in back pay and a possible order against the federal agency—forcing the agency to promote people who were the victims of discrimination, labor law attorneys told Bloomberg Law.

The case comes as age discrimination cases make up 21 percent of claims federal workers brought against their respective government...