Hydrogen Cyanide Leak at Delaware City Oil Refinery Has Been Fixed

Yesterday’s Dover Post says the leak has been fixed at the Delaware City Refinery, and there is no longer any release of hydrogen cyanide:

“Based on an analysis of the emissions, DNREC does not consider there to be a threat to public health,” said Michael Globetti, a spokesperson for the Department of Natural Resources and Environmental Control. “Even at its source within the refinery, the HCN now being released is exponentially less than the permissible threshold for exposure allowed under federal law.”

“The highest concentration of HCN was projected to occur approximately three-fourths of a mile from the source at a concentration of 3 parts per billion,” Globetti said. “By comparison, the Occupational Safety and Health Administration’s permissible exposure level to HCN without adverse effects is 10 parts per million.”

PBF Energy spokesperson Mike Gayda said that a low level concentration of about 10 parts per million was emitted into the air. He compared this to a drop of soy sauce in a pot of water.

Soy sauce? This is not soy sauce, it’s a deadly toxin. If you take a look at this table from the CDC’s website, you’ll see that while yes, exposure of 10 parts per million might be permissible, continuous exposure to that much becomes unpleasant pretty quickly:

Acute Exposure Guidelines
5 min 10 min 30 min 1 hr 4 hr 8 hr
(discomfort, non-disabling) – mg/m3
Not established/ determined 2.5 ppm 2.5 ppm 2.0 ppm 1.3 ppm 1.0 ppm
(irreversible or other serious, long-lasting effects or impaired ability to escape) – mg/m3
Not established/ determined 17 ppm 10 ppm 7.1 ppm 3.5 ppm 2.5 ppm
(life-threatening effects or death) – mg/m3
Not established/ determined 27 ppm 21 ppm 15 ppm 8.6 ppm 6.6 ppm

Note that DNREC said the highest concentration was “projected” to occur at a point 3/4 mile away from the source. “Projected” means they probably ran a computer model to simulate the leak, they didn’t take any measurements of the actual concentration of hydrogen cyanide in the air around the refinery. Was there a school close to that point? A playground? A church? Lots of what if’s, and not very timely disclosure to your neighbors.

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Just for clarification purposes, there was a release of 524 pounds of sulfur dioxide reported on 10/26 from the north flare at the Delaware City Refinery. It appeared to be a one time release and there have been no subsequent reports from the refinery since that date.