"An explosion and fire at Philadelphia Energy Solutions refinery has people concerned about hydrogen fluoride."
"The sirens went off about 4 a.m. Friday at the Philadelphia Energy Solutions refinery, following a warning that crackled over radios — a leak had been detected in “Unit 433.”
Unit 433 is an alkylation unit, one of several process units that convert crude oil into fuels and other products at PES, the East Coast’s largest refinery. The “Unit 433” name conveyed a special alarm to refinery workers.
The unit uses hydrogen fluoride as a catalyst, one of the most toxic materials handled in the refinery. In its gaseous state, it can drift beyond the refinery fence line and imperil the public.
Just seconds after the radio warning, the first of several explosions ripped through Unit 433, rattling the plant and lighting up the night sky. The fiery explosions, whose cause is unknown, injured five workers, unnerved the city, and caused gasoline markets to spike on speculation of fuel shortages."