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GRAND CANYON, Ariz. — A fire burning near the North Rim of Grand Canyon National Park triggered a dangerous release of chlorine gas Saturday afternoon after it damaged a critical water treatment facility, prompting emergency evacuations and widespread trail closures, park officials said.
According to the Grand Canyon Office of Communications, the incident occurred at approximately 3:30 p.m. on July 12, when firefighters battling the Dragon Bravo Fire discovered the facility ablaze. It was later confirmed that the fire led to a chlorine gas release, a hazardous situation that required swift response.
Why is chlorine gas dangerous?
Chlorine gas is heavier than air, meaning it can settle into low-lying areas like the inner canyon, where hikers and river runners may be exposed. Chlorine exposure can cause severe respiratory distress and other health risks, even at low concentrations.
In response, fire crews were pulled from the North Rim, and hikers were evacuated from the inner canyon. River trips were ordered to bypass Phantom Ranch, a popular stop for boaters traveling the Colorado River through the park.
Areas currently closed due to chlorine hazard
The following locations remain closed until further notice as a safety precaution:
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North Kaibab Trail
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South Kaibab Trail
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Phantom Ranch
Park officials said they are monitoring the situation and will reopen areas once safety assessments confirm that exposure risk has passed.
Monitoring the gas spread
Officials are using the NOAA HYSPLIT model, a forecasting tool designed to track the dispersion of airborne pollutants like smoke or gases, to assess the movement of the chlorine plume.
Current projections do not indicate a critical threat to neighboring communities. However, residents in Marble Canyon, Lees Ferry, and parts of the Navajo Nation may notice a chlorine odor in the coming hours or days.
What’s next?
Officials said more information would be released as it becomes available and are urging hikers, visitors, and nearby residents to stay informed through official park communications and emergency alerts.
This event underscores the unpredictable hazards posed by wildfires intersecting with infrastructure — particularly in remote and rugged areas like the Grand Canyon.