DAQ-2024-012158

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Salt Lake City Refinery
Tesoro Refining &
Marketing Company LLC
A subsidiary of Marathon Petrol6um Corporation
December 6,2024
Mr. Bryce Bird, Director
Utah Division of Air Quality
195 North 1950 West
PO Box 144820
Salt Lake city, uT 841l6-4880
HAND DELTVERED
Re: R307-107-2 Breakdown Renort
On November 25,2024,Tesoro Refining and Marketing Company LLC in Salt Lake City, Utah
(Tesoro) experienced excess opacity at the COB Bypass stack and visible emissions from the north
flare. These emissions occurred while the Carbon Monoxide Boiler (COB) experienced an
unplanned shutdown due to an instrument failure.
An initial notification of the breakdown was made by James Beardall to Jeremy Marsigli at l0:34
hours on November 25,2024. An additional notification was provided on the morning of November
26,2024 during the subsequent unit startup.
CAUSE/I.IATURE OF RELEASE AND CORRECTIVE ACTIONS:
Operators implemented procedures to safely secure the COB unit which also required an unplanned
shutdown of the Fluidized Catalytic Cracker Unit (FCCU). Procedures were implemented to restart
the COB and FCCU, and the faulty instrument was repaired, which enabled process gasses to be
returned to the COB, thereby eliminating excess opacity at the bypass stack. Flaring occurred during
the subsequent unit startup during intermittent periods when process gasses exceeded the capacity of
the facility's Flare Gas Recovery Unit.
SUMMARY OF DEVIATIONS:
COB Bypass Stack Opacityo Incident Date: November 25,2024o Incident Time: Excess opacity from approximately l0:25 till I l:08. Operational Limit: 20o/o opacity as a six-minute average
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DEC - 6 2024
DIVISION OF AIR OUAUTV
B-2-10335
Mr. Bryce Bird, Director
August 5,2024
North Flare Visible Emissionso Incident Date: November 25,2024o Incident Time: Intermittent visible emissions from 20:21 until 22:10 for an
aggregate period of 2l minutes. Operational Limit: 5 minutes in a 2-hour period
If you have any questions, please contact Chris Kaiser, of my staff at [phone].
/Ld,
Dean Anderson
Vice President
Tesoro Refining & Marketing Company LLC