Workers leave Hyundai Motor’s Ulsan plant early after a four-hour partial strike in Ulsan on Thursday. The union staged four-hour walkouts on Wednesday and Thursday before launching its first full-day eight-hour strike in 10 years on Friday. (Yonhap) Hyundai Motor labor union launched a full-day strike Friday, bringing production to a halt across the company’s key plants in South Korea as wage negotiations remain deadlocked.The walkout marks the first time since 2016 that members of the Hyundai Motor branch of the Korea Metal Workers’ Union have staged an eight-hour, full-day strike for each shift. The escalating strikes raise concerns that prolonged labor disruptions could undermine the automaker's push to revive domestic sales with new models in the second half.Production at Hyundai Motor’s plants in Ulsan, Asan, South Chungcheong Province, and Jeonju, North Jeolla Province, was suspended for the entire day Friday. Workers on the morning shift, which normally begins at 6:45 a.m., did not report for work; employees scheduled for the afternoon shift starting at 3:30 p.m. were also set to stay off work.With both shifts striking for eight hours, production lines were expected to remain idle for a total of 16 hours. About 39,000 union members, including production and office workers, are participating.The union has staged a series of partial strikes spanning two to six hours since wage negotiations began May 6, and Friday’s walkout brings the union’s cumulative strike time this year across two shifts to 120 hours.Industry officials estimate that the strikes have cost the company roughly 55,200 vehicles in production, based on Hyundai Motor’s hourly output of about 460 vehicles. That translates to more than 2.3 trillion won ($1.66 billion) in lost potential sales.The disruption could expand, with the union planning four-hour partial strikes on Monday and Tuesday.Labor and management resumed negotiations for the 16th bargaining session Monday after a break of more than 40 days following their failure to reach an agreement in the previous round. But the latest talks again ended without progress.“We will return to negotiations only when the company comes up with an improved proposal,” union chief Lee Jong-cheol said, leaving it unclear when formal talks will resume.The two sides remain divided over key issues, including the reinstatement of dismissed workers and an extension of the retirement age.At the 15th bargaining session in July, the company offered an 89,000-won increase in monthly base pay, a performance bonus equal to 350 percent of monthly base pay, 10 million won in cash and 15 Hyundai Motor shares per employee.The union rejected the offer. It is demanding a 149,600 won monthly base-pay increase, excluding regular seniority-based raises, and a performance bonus equivalent to 30 percent of the company’s 2025 net profit. It is also demanding guarantees on employment and working conditions related to the growing use of artificial intelligence.Other demands include introducing a fully fixed monthly salary system, raising annual bonuses to 800 percent of monthly base salary from the current 75 percent, introducing a 4-and-a-half-day workweek and extending the retirement age to as high as 65 in line with the eligibility age for the national pension.