The FLSA’s anti-retaliation provision prohibits “discharg[ing] … any employee because such employee has filed any complaint….” 29 U.S.C. § 215(a)(3) (emphasis added).
In 1993, the Second Circuit held that the anti-retaliation provision in the FLSA prohibits employers from retaliating against employees for filing formal complaints, instituting a proceeding, or testifying about FLSA violations, but does not encompass verbal complaints made to a supervisor. Lambert v. Genesee Hospital, 10 F.3d 46, 55 (2d Cir.1993)) (citations omitted).
On June 29, 2009, in Kasten v. Saint-Gobain Plastics, the Seventh Circuit followed when it held that, “the natural understanding of the phrase ‘file any complaint’ requires the submission of some writing to an employer, court, or administrative body.”