California Declares Emergency After Overheating Chemical Tank Triggers 40,000 Evacuations

Overview

• Authorities ordered about 40,000 residents to evacuate and isolated roughly 23 square kilometers after vapors from a storage tank prompted a major response on Friday, May 22.
• The tank holds roughly 22,700–26,500 liters of methyl methacrylate, a highly volatile and flammable chemical used to make plastics, and could either spill or enter a thermal‑runaway that might damage nearby tanks.
• Automatic safety systems including a relief valve and sprinklers activated and emergency crews have poured water, built containment barriers and worked to keep any runoff out of storm drains and waterways.
• Responders discovered mechanical damage to a valve that has prevented safe removal of the product, officials briefly paused and then reinstated evacuation orders, and about 6,000 people reportedly refused to leave their homes.
• No injuries have been reported, the governor declared a state of emergency, and officials say continuous monitoring will continue with no timeline yet for when residents can safely return.