UPDATE 1-Valero says worker died after chemical exposure

Mon Dec 3, 2012 6:04pm EST

HOUSTON Dec 3 (Reuters) - One of two workers exposed to a hazardous chemical at Valero Energy Corp's Tennessee refinery early on Monday has died, the company said.

Both were hurt when a small window on a unit ruptured at the 180,000 barrels-per-day (bpd) Memphis refinery, spokesman Bill Day said. He said the sight glass failed on an alkylation unit, injuring a Valero employee and a contractor.

The Valero employee, who not identified, later died, Day said.

Memphis Fire Department spokesman Lt. Wayne Cooke and Day said responders were investigating what chemicals were behind the glass that ruptured.

Sources familiar with refinery operations said the chemical was hydrogen flouride, which can cause severe burns if in contact with skin or breathed into lungs. When dissolved into water, the chemical also can be called hydroflouric acid.

The incident did not involve an explosion or fire as some local media reports initially said. Valero said refinery operations were not affected.

Last March, three workers at the Memphis refinery were hurt in a flash fire during an overhaul of a crude distillation unit. One of the workers later died.