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.


        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.