Video of the 1986 “Goldfish” Release Test of hydrofluoric acid (HF), one of the world’s most dangerous industrial chemicals, shows the formation and spread of a ground-hugging toxic cloud. The test, carried out by Lawrence Livermore National Laboratory research scientist Dr. Ronald R. Koopman, simulated the accidental release of superheated HF from a small rupture in the bottom of an alkylation-unit settler tank. The video shows a test where 8,300 lbs. of HF were released within 2 minutes.
Although the test was carefully designed and constructed to catch and weigh the amount of HF that fell to the ground, to the great surprise of the researchers, 100% of the HF became airborne in a dense, ground-hugging cloud. None fell to the ground. Two miles downwind, the HF cloud had more than twice the lethal concentration. Consider that each of the two settler tanks at the Torrance Refinery holds 50,000 lbs. of HF — six times more than the 1986 “Goldfish” Release Test.
Compare these “Goldfish” test results to the large-scale accidental release of 84,00 lbs. of sulfuric acid at the Tesoro Refinery in Martinez, California, on February 12, 2014. In contrast to superheated HF, sulfuric acid used in refineries is highly subcooled. There was no formation of an aerosol cloud. All the acid fell to the ground, and there were no offsite consequences.
While the Torrance and Wilmington Valero refineries use Modified Hydrofluoric Acid (MHF) with 6-10% sulfolane to reduce vapor pressure and hence the amount of superheat, the amount of sulfolane is far too little to prevent a toxic cloud, a fact that has been confirmed by both the TRAA Science Advisory Panel and the SCAQMD Technical Staff.
Besides sulfuric acid, which has long been used at Chevron’s El Segundo refinery, other modern alkylation catalysts are now commercially available that are vastly safer than HF. A third U.S. HF refinery has just announced it is converting to one.
Click the image above to watch the video and click the title below to read the 1988 Los Angeles Times article on the test:
Experts Warn of Lethal Risk Posed by Acid in L.A. Refineries