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Although rare, natural and human-induced CO₂ leaks have occurred with devastating consequences

Summary​

While rare, both natural and human-caused carbon dioxide leaks have led to tragic consequences. Three notable cases demonstrate these risks: The 1989 Lake Nyos disaster in Cameroon killed 1,800 people through a natural limnic eruption. The 2020 Satartia, Mississippi pipeline rupture hospitalized 46 people and revealed emergency response challenges. California's ongoing Mammoth Mountain leak releases 300 tons of CO₂ daily, with fatal incidents occurring in 2006. These events highlight the dangers of concentrated CO₂ exposure and the importance of preparedness, particularly as CO₂ pipeline networks expand for industrial use.

Carbon dioxide (CO₂) leakages pose a risk to the environment and local residents. Fatal natural releases of CO₂ such as from volcanic craters are rare. However, if they are located near population centers they can be deadly. Anthropogenic (human-induced) CO₂ leaks are more common due to the extensive CO₂ pipeline system that feeds the Enhanced Oil Recovery (EOR) industry. However, we have been fortunate that these leaks have not caused many fatalities. Some notable natural and anthropogenic CO₂ leaks are listed below.

The Lake Nyos disaster (Cameroon, 1989)​

The Lake Nyos disaster was a natural CO₂ leak that occurred in Cameroon in 1989 and is the deadliest CO₂ leak in history. The disaster occurred due to a limnic eruption located in the crater which formed Lake Nyos. A limnic eruption occurs when water with high concentrations of dissolved CO₂ suddenly rises to the surface where the CO₂ is released and degassed. After the eruption, at least 100,000 tons of CO₂ were released, and due to carbon dioxide being denser than air, the gas cloud initially moved down the valley into nearby villages, killing close to 1,800 people and many thousands of animals 1. Those closest to the eruptions suffocated immediately due to inhalation of the highly concentrated CO₂, many in their sleep as it was nighttime. Others further away from the eruption lost consciousness and woke up the next day 1. Initially, there was much speculation as to whether the cause of death was due to the CO₂ or other toxic gases such as sulfur or carbon monoxide; however, testing of the lake showed that CO₂ was the primary gas with elevated concentrations 2. Most of the survivors of the disaster were able to recover relatively quickly without long-term effects, yet still an estimated 15,000 people were displaced, many of whom remain as internally displaced people to this day 1. There have only been two recorded limnic eruptions in history, the other being the Lake Monoun disaster in 1986 also located in Cameroon. The only other known lake containing supersaturated CO₂ is Lake Kivu on the border of the Democratic Republic of Congo and Rwanda 1.

The Satartia gas leak (USA, 2020)​

The Satartia gas leak in Mississippi is the most prominent mass exposure CO₂ leak to occur recently in the United States. The leak occurred due to a rupture of a CO₂ pipeline owned and operated by the oil company Denbury, used to transport CO₂ from a nearby volcano in Jackson, Mississippi, to nearby oil fields for EOR 3. Immediate reports after the rupture recounted that a green fog (now known to be the CO₂ gas cloud) engulfed the area, and first responders immediately attempted to rescue the few hundred residents that lived in and around Satartia. Overall, more than 46 residents were hospitalized, but no fatalities were recorded 3. Many of the victims of the disaster report continued symptoms and including lasting mental health issues such as anxiety that have not allowed them to return to their lives before the accident. The main consequence of the disaster was the realization of how underprepared first responders are to react to a CO₂ leak. First responders on the scene had no specialized training to deal with CO₂ leaks. When they first arrived at Satartia, many reported scenes reminiscent of a "zombie movie" with victims in delirious states due to the poisoning, walking around in circles and unable to understand basic instructions such as calls to get into cars to evacuate 3. Additionally, standard combustion engines are unable to operate in the presence of high concentrations of CO₂, which meant that the engines of the vehicles of first responders and those evacuating began to stall 3. As of 2021, there were 5,000 miles of CO₂ pipelines in the United States, but there are calls mainly from the oil industry to expand the network to 65,000 miles by 2050 to further fuel the EOR industry 3.

Mammoth Mountain gas leak (USA, ongoing)​

The Mammoth Mountain gas leak located in California is an ongoing natural volcanic CO₂ leak that was first identified by scientists in 1989. Research indicates that an estimated 300 tons of CO₂ is leaked from the mountain per day 4. The most obvious signs of the gas leak are a large area of almost 100 acres which contains dead and dying vegetation. Trees require atmospheric CO₂ to survive, but they also need the soil to be oxygen-rich, which they absorb through their roots. Testing of the soil in the dead vegetation area shows that 95% of the gas content is CO₂, compared to normal soil concentrations of around 1% 4. In 2006, three ski patrol members at Mammoth Mountain were killed by CO₂ asphyxiation when they fell into a nearby geothermal vent that they were cordoning off 5.

Sources​

Footnotes​

  1. FORKA LEYPEY, M. F. (2011). The Strange Lake Nyos CO2 Gas Disaster: Impacts and the Displacement and Return of Affected Communities. The Australasian Journal of Disaster and Trauma Studies, 1. ↩ ↩2 ↩3 ↩4

  2. Baxter, P. J., Kapila, M., & Mfonfu, D. (1989). Lake Nyos disaster, Cameroon, 1986: The medical effects of large scale emission of carbon dioxide? BMJ (Clinical Research Ed.), 298(6685), 1437-1441. https://doi.org/10.1136/bmj.298.6685.1437 ↩

  3. Zegart, D. (2021, August 26). The gassing of Satartia: Inside the Mississippi pipeline disaster that left dozens dizzy and gasping for air. HuffPost. Retrieved from https://www.huffpost.com/entry/gassing-satartia-mississippi-co2-pipeline_n_60ddea9fe4b0ddef8b0ddc8f ↩ ↩2 ↩3 ↩4 ↩5

  4. U.S. Geological Survey. (2000). Invisible CO₂ gas killing trees at Mammoth Mountain, California (Fact Sheet 172–96, version 2.0). Retrieved from https://pubs.usgs.gov/dds/dds-81/Intro/facts-sheet/fs172-96.pdf ↩ ↩2

  5. Covarrubias, A., & Smith, D. (2006, April 7). Tree deaths on Mammoth Mountain linked to underground gases. Los Angeles Times. Retrieved from https://www.latimes.com/archives/la-xpm-2006-apr-07-me-mammoth7-story.html ↩