Timeline of Events

Tosco Avon Fire

February 23, 1999

California Department of Industrial Relations

Division of Occupational Safety and Health

February 10, 1999

· Visible Leak observed at approximately 1:00 p.m. from the fractionator tower block valve on the naphtha draw line, 50-unit fractionator

· Steps taken to isolate and stop leak on naphtha draw line.

· Naphtha draw line stops leaking.

· Work requests for repair/replacement of naphtha draw line.

February 11, 1999

· Inspection determines thinning in top section of naphtha draw line.

February 11-17, 1999

· Additional inspection of naphtha draw line.

· On 2/13/99, leak reappears at site of leak noticed on 2/10/99; naphtha stripper refills with naphtha, valves are retightened and naphtha stripper is pumped out.

February 17, 1999

· Original leak site on naphtha draw line resumes weeping.

· Valves re-tightened, naphtha stripper pumped out again.

· Bleeder valves in line noted as plugged.

February 18, 1999

· Attempt to clear bleeder valves fails.

February 19, 1999

· Line work continues.

· Line again inspected.

February 22, 1999

· Preparation for line removal next day.

Timeline: Tosco Avon Fire (Continued)

February 23, 1999

· Work on naphtha draw line (NDL) in preparation for its removal.

· Attempts to drain reveal control valve sludged up after being blocked in.

· Top section of NDL is cut and removed to grade.

· Further attempts to drain NDL again fail. Solid plugging found.

· Liquid leaks from NDL as second cut is made.

· Lunch

· Draining operation continues and second cut on NDL resumes.

· Naphtha leaks out second cut, then top cut of NDL, dousing workers.

· Fire breaks out at 12:10 p.m.

· Initiation of emergency shutdown of 50-Unit Fractionator and firefighting/rescue efforts.

· Fire under control at 12:38 p.m.