Explosion Risk of Cardiac Implantable Electronic Devices During Cremation: Experimental and Survey Findings From Japan

Background: The widespread use of cardiac implantable electronic devices (CIEDs), combined with increasing global cremation rates, has raised concerns regarding potential explosion risks during cremation. Lithium batteries within these devices may rupture due to heat-induced internal pressure, potentially threatening crematorium infrastructure and staff safety. Despite these concerns, real-world data on explosion behavior and its consequences remain limited. This study aimed to assess the explosion characteristics of CIEDs during cremation and evaluate their impact on facility safety, with the goal of informing evidence-based guidelines. Methods: Combustion experiments were performed using full-scale cremation furnaces set at 1100°C and 800°C. A total of 13 CIEDs (7 pacemakers and 6 implantable cardioverter-defibrillators) were tested, with synchronized audio-video monitoring. Additionally, nationwide survey data were collected from 2044 crematoria across Japan, focusing on cremation practices, reported damage, and staff injuries. Results: All tested devices exploded, with mean ignition-to-explosion times of 4.3 ± 1.1 min at 1100°C and 5.4 ± 2.0 min at 800°C (p = 0.19). Seventeen explosion events were observed, yet no structural damage to the chambers occurred. Survey data revealed a decline in cremation refusal due to CIEDs—from 11.0% in 2012 to 4.6% in 2013 and 3.0% in 2014 (p < 0.001). According to respondents, this trend likely reflects an increased collaboration with medical associations, modernization of crematorium facilities, and dissemination of practical safety information. Conclusions: Cremation of CIEDs without removal appears safe under modern, regulated facilities. However, region-specific guidelines remain necessary due to international variability in infrastructure and practices.