GRAND CANYON, AZ.—On July 12, at approximately 3:30 p.m., firefighters responding to the Dragon Bravo Fire on the North Rim in Grand Canyon National Park reported that the North Rim water treatment facility had caught fire. It was later confirmed that chlorine gas was released from the treatment facility.
Chlorine gas is heavier than air and can quickly settle into lower elevations such as the inner canyon, posing a health risk. Due to the risk of exposure, park authorities immediately evacuated firefighters from the North Rim and hikers from the inner canyon, and closed access to specific areas within the inner canyon. All river trips were instructed to bypass Phantom Ranch.
The following inner canyon locations remain closed until an assessment is completed, and it is deemed safe to reopen: North Kaibab Trail, Phantom Ranch, and the South Kaibab Trail.
Current HYSPLIT maps from NOAA indicate that the chlorine gas does not pose a critical threat to nearby communities. The HYSPLIT model is used to predict the spread of gases or smoke in an identified area when they are released. The most recent HYSPLIT map can be viewed by clicking here:
https://www.hysplit-pub.noaa.gov/hysplitpublic-bin/hyresults.pl?jobidno=25792
Residents in Marble Canyon, Lees Ferry, and a small area of the Navajo Nation may detect the smell of chlorine in the near future. The park will provide more information as soon as it is available.
