What started as “workplace morale” problems for Chipotle has snowballed into a huge class-action lawsuit over unpaid wages. A daunting number of employees — 9,961, or roughly 1 in 5 — have joined the complaint, which claims the chain “routinely requires hourly-paid restaurant employees to punch out, and then continue working until they are given permission to leave.” Managers allege they also had to work without pay, and were required to shortchange staff in order to “meet budget goals,” as CNNMoney explains it.

Wage-related lawsuits aren’t uncommon at big chains, sadly, but this one is really giant — the largest ever against the company. Kent Williams, the attorney working the case, says there are plaintiffs in almost every state that has a Chipotle location. “Chipotle has argued this is a few rogue managers who aren’t following policy,” he notes. “Our view, especially given the number of people opting in, is that it’s a systematic problem at Chipotle.”

“Dozens” of workers tell CNNMoney they’ve seen the wage theft occur at their stores, and many add they often put in five hours or more of free labor every week. The lion’s share of complaints appear to relate to closing down stores:

Chipotle denies any wrongdoing and argues it has paid all wages it owes employees. It’s promising to fight the case in court.