Lessons from a Toxic Cloud

[patric]

No one was killed, but, as it was made plain days later in a company announcement, their jobs were going up in smoke along with the liquefied petroleum gas that was burning.
Had the blast released a potentially lethal cloud of Hydrogen Fluoride, within 10 minutes it could have traveled as far as seven miles. More than a million people live within that area.
https://www.inquirer.com/news/philadelphia-refinery-fire-explosion-timeline-hero-rescuers-20190629.html
https://www.nbcphiladelphia.com/news/local/Blast-Rocks-Philly-Refinery_Philadelphia-511616932.html


"There's no place to evacuate to, and there would be no time."
...most of the releases were caused by explosions or fires, which force the HF above ground level, where it can mix with air and reduce the hazard. In such a case it's possible HF could be released but not measured by any monitors near the ground.
https://www.publicradiotulsa.org/post/refinery-explosions-raise-new-warnings-about-deadly-chemical


In another incident, a cloud of gases was released from an oil refinery near Tulsa, Oklahoma, on March 19, 1988. The major constituent of the cloud was HF, which may have reached an airborne concentration of 20 ppm. A total of 36 people, including emergency personnel responding to the incident, were treated at area hospitals for acute chemical exposure. There were no fatalities. No measurements were taken and no further details of the incident were given.
https://www.nap.edu/read/10902/chapter/6