What happened

A mudslide ruptured Denbury's 24-inch carbon-dioxide pipeline about a mile from Satartia, Mississippi, releasing an estimated 21,873 barrels of liquid CO2 as a dense, ground-hugging green fog that displaced oxygen. Roughly 200–300 residents were evacuated and 45–49 people were hospitalized for CO2 exposure, some found collapsed in their homes; no one was killed. PHMSA fined Denbury nearly $3.9 million, among the largest civil penalties in the agency's history, and the incident became a reference case for the safety risks of proposed CO2-pipeline networks. This was an accidental pipeline failure, not an attack.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.