"CORPUS CHRISTI -- A fire last month at a local Citgo refinery has focused attention on what is likely the most dangerous chemical used in the refining process.
Hydrogen fluoride, an acid, is used as a catalyst for chemical reactions in the alkylation unit, which produces a high-octane component for gasoline. The Citgo alkylation unit was the site of the July fire and another in 1997.
Environmental groups, worried about the risk of a hydrogen fluoride vapor cloud, are pushing for safer alternatives. But each method has its drawbacks.
The only other proven chemical for alkylation is sulfuric acid, which like hydrogen fluoride can burn skin, tissue and lungs, though sulfuric acid is generally considered less toxic and less lethal. The third choice, a solid mineral that can be handled safely, hasn’t been tested in commercial-scale refineries.
Industry and academic experts say a switch is expensive and difficult. But the fire, which severely burned a Citgo worker, is an opportunity to open debate, environmentalists say."