Dramatic Large-Scale Demonstration that Sulfuric Acid Is Far Safer than MHF for Alkylation

Loss of containment, from a tubing separation (yellow oval) after the valve (red square) was opened, released 84,000 pounds of sulfuric acid at the Tesoro Refinery in Martinez, California. There were no offsite consequences.

The U.S. Chemical Safety Board (CSB) reported on an accidental release of 84,000 pounds of sulfuric acid over two-and-a-half hours from an alkylation-unit settler tank at the Tesoro Refinery in Martinez, California, on February 12, 2014. The release was onto the refinery grounds and into a process sewer system. There was no vapor cloud or offsite consequences to the community. The spill burned two workers, who were transported to the nearest hospital burn unit by helicopter. They survived and returned to work after five months.

A Modified Hydrofluoric Acid (MHF) release of this magnitude would have had cataclysmic consequences not only for refinery workers, but also for the surrounding community. A ground-hugging toxic cloud would be lethal for more than eight miles downwind. (For comparison, there are 50,000 pounds of MHF in one Torrance refinery settler tank.) This full-scale incident is further dramatic evidence that sulfuric acid alkylation is far safer than MHF alkylation, contrary to the claims of ExxonMobil and the Torrance Refining Company.

A leader in sulfuric acid alkylation, DuPont offers a cost-effective alkylation conversion  from volatile and toxic hydrofluoric acid (HF) alkylation units to safer sulfuric acid alkylation technology.