A “minor incident” at a Foxconn factory in Chengdu, China sparked a riot on Monday as a number of workers attacked company security guards. Despite Apple’s efforts to improve conditions in it’s partners’ factories, workers are still displeased. Following an incident involving a theft in a factory dormitory, some employees with grudges against the security guards jumped at the chance to retaliate. The event soon escalated, with more than a thousand workers joining in by throwing trash cans and destroying facilities, Want China Times reported. Foxconn security guards were forced to call the police, who arrived at the scene by the hundreds. The riot lasted for two hours and dozens of workers were reportedly arrested. The plant produces liquid crystal displays for Apple’s iPhone and is the same factory where an explosion killed two workers and injured 16 others last May.