A union that’s organizing Waffle Houseworkers filed a petition with the Labor Department on Monday, asking federal officials to investigate the iconic chain’s policy of deducting mandatory meal costs from workers’ paychecks.

Waffle House takes at least $3 for each on-shift meal out of workers’ pay, whether they end up eating it or not, according to the petition from the Union of Southern Service Workers. The USSW called it “especially alarming” since many workers are paid a tipped sub-minimum wage “as low as $2.90 per hour,” not including gratuities.