This legislation, titled the "Extreme Temperatures Injustice in Prisons Act of 2026," directs the Director of the Bureau of Prisons (BOP) to significantly improve environmental controls in federal correctional facilities. Within five years of enactment, the Director must install or update all heating, ventilation, and air conditioning (HVAC) systems and place temperature reading devices in every space occupied by humans, including individual cells and common areas. During this interim period, the Director is also required to regularly monitor temperatures across these facilities. The bill mandates the development and enforcement of comprehensive written standards to address both heat stress and cold stress for incarcerated individuals, covering work operations, recreational activities, and all conditions of confinement. Additionally, the Director of the Centers for Disease Control and Prevention (CDC) will study the health effects of extreme temperatures in these facilities and recommend safer practices. Based on CDC guidance, the BOP Director must finalize rules within one year to establish mandatory standards specifically protecting medically vulnerable populations. To safeguard staff, the BOP Director must implement NIOSH-recommended exposure and alert limits based on wet-bulb globe temperature to account for humidity in occupational heat exposure. Furthermore, the bill requires the availability of free mitigation options for inmates, such as cold-water bottles and cooling fans during extreme heat, and winter clothing and blankets during extreme cold, provided outside of the commissary. An electronic record-keeping system will also be established to track seasonal training for personnel on winter mitigation and identifying heat-related illness symptoms. The legislation includes robust reporting and oversight mechanisms. The BOP Director must submit biennial reports to Congress on HVAC maintenance costs and installation progress, and annual reports on temperature-related illnesses, injuries, and fatalities among vulnerable populations. Annually, the Inspector General of the Department of Justice will conduct oversight inspections of temperature devices, HVAC systems, health outcomes, and mitigation efforts, publishing findings to ensure compliance and accountability.