Seoul: The Supreme Court on Thursday upheld a lower court's ruling that HD Hyundai Heavy Industries Co. has no obligation to respond to the collective bargaining demands from a union of in-house subcontractor workers. According to Yonhap News Agency, the lawsuit was filed in 2017, and the Supreme Court ruled under the old labor law rather than a revised version, dubbed the "yellow envelope act," which took effect in March this year. The new law expanded subcontracted workers' bargaining rights while increasing the accountability of prime contractors. The unionized subcontractor workers demanded collective bargaining with HD Hyundai Heavy Industries in 2016, asserting that the prime contractor held a position of substantial control over their working conditions. As the demand was not accepted, the workers filed the lawsuit in January 2017. District and appellate courts dismissed the workers' claim, stating that the shipbuilder was not obligated to engage in collective bargaining with them. The courts reason ed it is difficult to acknowledge an implicit employment relationship between them, considering subcontractors' independent payroll, hiring, and personnel management systems. The Supreme Court has been reviewing the case since December 2018 after the union appealed the ruling. The central issue was whether HD Hyundai Heavy Industries, the prime contractor, has an obligation to respond to the demands of the in-house subcontractor workers for collective bargaining regarding union activities, industrial safety, and employment security.