The Philippine National Security Council, together with the Philippine Navy and Bureau of Investigation, announced on Monday the findings of an investigation concluding that Chinese Maritime Militia vessels used cyanide in waters surrounding the BRP Sierra Madre — a deliberately grounded naval ship that serves as the Philippines' military outpost at Ayungin (Second Thomas) Shoal in the disputed West Philippine Sea. The revelation marks a significant escalation in tensions between Manila and Beijing over the contested shoal, where Chinese and Philippine forces have repeatedly clashed in recent months. The use of a toxic chemical near stationed Filipino troops adds a new and alarming dimension to the ongoing territorial dispute.