Volcanoes often feel like a far away threat, like something out of an adventure movie for most folks. But the United States is home to some of the most dangerous and potentially deadly volcanoes in the world. As part of the Pacific Ring of Fire, the country has numerous active and dormant volcanic systems that pose serious threats to nearby communities. These volcanoes not only present dangers from lava flows and eruptions but also release hazardous gases, even when they are dormant.
Understanding these risks is critical for both public safety and environmental health. Especially when you realize that volcanic eruptions “can last days, months, or even years.”1
Hazardous Gases Released by Volcanoes
Magma holds dissolved gases that serve as the primary impetus for most volcanic eruptions. As magma ascends towards the surface and encounters reduced pressure, gases are expelled from the molten part of the magma and continue to rise, ultimately escaping into the atmosphere. Significant eruptions can release vast amounts of gas into the air rapidly.
For instance, the eruption of Mt. Pinatubo (Philippines) in 1991 is believed to have emitted over 250 megatons of gas into the upper atmosphere within a single day. Even if magma does not reach the surface, gases can still seep out continuously from soil, volcanic vents, fumaroles, and hydrothermal systems.
Remember – dangerous gases are released from volcanoes that are dormant too.2 After water vapor, which is harmless, the primary volcanic gases include:
Carbon Dioxide (CO₂)
This gas can accumulate in low-lying areas, creating asphyxiation hazards. Since it is heavier than air, CO₂ can settle into valleys and basins, posing risks to people and animals.
Sulfur Dioxide (SO₂)
This gas can cause respiratory problems and contribute to acid rain, which damages ecosystems and infrastructure.3
Hydrogen Sulfide (H₂S)
Known for its rotten egg smell, this gas is highly toxic in high concentrations and can cause respiratory distress and neurological effects.
Carbon Monoxide (CO)
A colorless, odorless gas that interferes with oxygen transport in the blood, leading to suffocation.
Hydrogen Halides (HCl, HF)
These acidic gases can cause severe respiratory irritation, skin burns, and environmental damage.
Remember – even dormant volcanoes can release gases through fumaroles and hot springs, posing ongoing risks to those who live near them.
Seven U.S. Volcanoes That Could Erupt in the Near Future
The U.S. Geological Survey (USGS) closely monitors volcanic activity through its Volcano Hazards Program, tracking seismic activity, ground deformation, and gas emissions.4
The following are volcanoes in the U.S. that are anticipated to erupt in the near future (in alphabetical order) according to experts:
Great Sitkin, Alaska
This volcano is currently under “watch” (the second highest threat level), as Great Sitkin has been erupting lava consistently in recent weeks. It became active with an explosion in spring 2021 and began to erupt in July of that year. It is located in the Aleutian Ridge, a sparsely populated area (25 miles from the nearest settlement), but still poses a threat if it becomes more volatile.5
Kīlauea, Hawaii
One of the most active volcanoes in the world, Kīlauea frequently erupts – most recently as last month. It releases vast amounts of lava and dangerous gases like sulfur dioxide during these events. The USGS expects further, more disruptive eruptions in the coming years, making ongoing monitoring crucial.6
Mauna Loa, Hawaii
The world’s largest volcano, Mauna Loa, has a history of frequent and extensive lava flows. Its vast underground lava tubes and sheer size make eruptions difficult to predict. When active, it releases large amounts of sulfur dioxide, affecting air quality across the Hawaiian Islands.
Mount Rainier, Washington
This towering stratovolcano is particularly dangerous due to its glaciers. An eruption could trigger massive lahars (volcanic mudflows), endangering surrounding areas. Mount Rainier releases gases such as sulfur dioxide and carbon dioxide even in its dormant state.
Mount St. Helens, Washington
Known for its catastrophic 1980 eruption, Mount St. Helens remains a highly active volcano. It continues to experience seismic activity and releases sulfur dioxide and carbon dioxide, making it a persistent threat to nearby communities.
Redoubt Volcano, Alaska
Redoubt is notorious for its frequent eruptions and significant ash plumes. It poses a serious risk to aviation and nearby infrastructure, with past eruptions shutting down air traffic in the region. It releases sulfur dioxide, carbon monoxide, and other toxic gases.
Yellowstone Supervolcano, Wyoming
Perhaps the most infamous of all, Yellowstone is a supervolcano with the potential for a catastrophic eruption. Though it has not erupted for over 600,000 years, it continuously releases carbon dioxide and hydrogen sulfide through its geysers and hot springs. Scientists closely monitor ground deformation and gas emissions to assess any changes in activity.
Monitoring and Mitigating Volcanic Hazards
The USGS Volcano Hazards Program plays a crucial role in monitoring these volcanic systems. Mount St. Helens, in particular, is under constant surveillance through seismic activity tracking, gas emissions analysis, and satellite imaging. This ongoing research helps provide early warnings, giving communities time to prepare for possible eruptions.
Protecting Indoor Air Quality in Volcanic Regions
For those living near active or dormant volcanoes, exposure to hazardous volcanic gases is a significant concern. Protecting indoor air quality is essential to reducing health risks. The Austin Air HealthMate Plus is an excellent solution for individuals in these regions.
The HealthMate Plus is equipped with activated carbon impregnated with potassium iodide, which enhances its ability to adsorb dangerous gases like sulfur dioxide and hydrogen sulfide. This advanced filtration provides peace of mind to anyone living near a volcano, where air quality can fluctuate unpredictably.
An added benefit is that the Austin Air HealthMate Plus is also the best option for wildfire smoke, which frequently impacts volcanic areas in the United States. With its combination of medical-grade HEPA filtration and specialized activated carbon, it effectively removes fine particulate matter, harmful gases, and toxins associated with both volcanic activity and wildfires.
Final Thoughts
Volcanoes in the United States are more than just awe-inspiring natural wonders—they are dynamic and potentially dangerous geological features. Whether active or dormant, they release hazardous gases that can pose risks to human health, ecosystems, and infrastructure. Through advanced monitoring and preparedness efforts, scientists aim to mitigate these dangers and keep communities safe.
As volcanic activity continues to shape the landscape, staying informed about potential threats remains essential. Additionally, investing in high-quality air filtration, such as the Austin Air HealthMate Plus, can provide an added layer of protection for those living in volcanic regions, ensuring cleaner, safer air indoors – something that is especially important for folks with asthma, COPD, or other chronic respiratory conditions.
REFERENCES
1About volcanoes. (n.d.). United States Geological Survey. https://www.usgs.gov/programs/VHP/about-volcanoes.
2 Volcanic gases can be harmful to health, vegetation and infrastructure. (n.d.). United States Geological Survey. https://www.usgs.gov/programs/VHP/volcanic-gases-can-be-harmful-health-vegetation-and-infrastructure.
3 Carn SA, Fioletov VE, McLinden CA, Li C, & Krotkov NA. (2017 March 9). A decade of global volcanic SO2 emissions measured from space. Scientific Reports, 7(1). https://doi.org/10.1038/srep44095.
4 Volcano Hazards Program. (2025 February 20). United States Geological Survey. https://www.usgs.gov/programs/VHP.
5 Great Sitkin. (2025 February 20). Alaska Volcano Observatory. https://avo.alaska.edu/volcano/great-sitkin.
6 Kīlauea – Volcano updates. (2025 February 20). United States Geological Survey. https://www.usgs.gov/volcanoes/kilauea/volcano-updates.
