这场致20人死亡的悲剧是如何发生的？监控还原事发经过

Core Viewpoint - The investigation report on the major fire accident at the Guo'en Elderly Apartment in Chengde, Hebei Province, reveals that the fire was caused by a short circuit in the power supply line connected to an electric anti-decubitus air mattress, leading to the tragic loss of 20 lives and significant economic damage of 12.748 million yuan [1][3][12] Group 1: Accident Details - The fire occurred on April 8, 2025, in the Guo'en Elderly Apartment, resulting in 20 fatalities and the rescue of 33 individuals by firefighters [1] - The direct cause of the fire was identified as a short circuit in the electrical wiring, which ignited surrounding combustible materials [3][6] - The apartment's failure to implement fire safety responsibilities and the use of unqualified electrical equipment were significant contributing factors to the accident [3][12] Group 2: Investigation Findings - The investigation revealed that the building was originally designed as a two-story structure but was completed as three stories, with inadequate fire safety measures [5] - The fire alarm system failed to alert staff for 19 minutes after the fire started, delaying the response [5][8] - The apartment's fire control room was not staffed adequately, violating regulations that require 24-hour monitoring [8][10] Group 3: Safety Violations - The use of flammable materials, such as polystyrene sandwich panels, in the building's construction contributed to the rapid spread of the fire [5][12] - The staffing levels were insufficient, with only two caregivers present for 19 non-self-sufficient elderly residents, which did not meet the required caregiver-to-resident ratio [8][10] - Emergency call devices were not installed in the elderly residents' rooms, preventing them from alerting staff during the fire [10]