Two workers in their 40s died after falling from the 11th floor of an apartment building in Busan when a balcony railing gave way during the installation of an outdoor air-conditioning unit, authorities said Thursday. An apartment building in Suwon where outdoor air-conditioning units are installed on window railings (123rf) The accident occurred around 12:20 p.m. Wednesday at a 39-year-old apartment complex in Sasang-gu, Busan.According to police, one worker fell after the structure gave way, and the second worker fell while attempting to grab and save his colleague.Both men suffered cardiac arrest and were transported to a hospital, but were later pronounced dead.Investigators said the aging railing structure appears to have collapsed under the combined weight of the outdoor unit and the worker leaning on it. Outdoor air-conditioning units are mounted outside an apartment building in Busan. Such installations were common in older apartment buildings constructed before regulations were revised in 2006 to require designated balcony space for outdoor units. (Yonhap) The apartment building was constructed in 1987, before regulations were revised in 2006 to require outdoor air-conditioning units to be installed on apartment balconies rather than attached outside railings after repeated safety accidents.Authorities are investigating the exact cause of the accident.