Hovensa’s catalytic cracker’s stacks released more than a ton of highly toxic hydrogen cyanide gas and a smaller amount of ammonia recently, the refinery reported to the U.S. Environmental Protection Agency Friday in response to a recent industry-wide survey.
According to a notice filed with the U.S. Coast Guard’s National Response Center, Hovensa released 2,648 pounds of hydrogen cyanide and 237 pounds of ammonia. Catalytic cracking is an integral part of refining crude oil into gasoline, gases and other substances.
"Because levels for ammonia and hydrogen cyanide at the FCC stack were found to be above established reportable quantities, we made the appropriate notifications on Friday," Hovensa spokesman Steve Strahan said Monday in an email. "To understand the potential impact of these levels, we performed dispersion modeling using an EPA tool which showed that the levels detected were within EPA exposure limits for public health. We will continue to monitor this situation."
Strahan did not say how long the release lasted or if the entirety occurred in a single episode or over time.
Hydrogen cyanide is liquid below 79 degrees Fahrenheit and becomes gaseous above that temperature. It is lethal in 10 minutes at 300 milligrams per cubic meter.
