UPDATED Media Statement: MDEQ response continues at Marathon in Southwest Detroit

For Immediate Release:
February 4, 2019

Contact:
MDEQ Media Office, deq-assist@michigan.gov, 517-284-9278

MDEQ response continues at Marathon in Southwest Detroit

Updated Statement:

The Michigan Department of Environmental Quality (DEQ) continues to coordinate with EPA and the City of Detroit on air monitoring and response activities related to the malfunction of the coker flare gas system and resulting odors from the Marathon refinery in Detroit.

DEQ, City of Detroit, and EPA staff met with Marathon personnel at the refinery today and were briefed on steps taken to reduce and reroute gas normally combusted by the flare system in an effort to reduce the rotten egg odors being emitted from the refinery.  Marathon also briefed DEQ on plans to safely shut-down the refinery in the coming days to make repairs to the coker flare gas system. 

The source of the odors created by the flare gas system are suspected to be hydrogen sulfide and mercaptan compounds. Both of these compounds have extremely low odor thresholds meaning they can be smelled even at very low levels.

Apart from the odor, neither EPA’s or Marathon’s air quality sampling have detected any exceedances of health thresholds.  DEQ’s Air Quality Division is reviewing monitoring data from DEQ’s own ambient air monitoring stations in the area in addition to reviewing the Marathon data. 

A follow-up meeting is scheduled with the company and government officials tomorrow afternoon.

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