Media Statement: MDEQ Continues to Coordinate with EPA and City of Detroit following Marathon Refinery Shutdown

For Immediate Release:
February 7, 2019

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

MDEQ Continues to Coordinate with EPA and City of Detroit following Marathon Refinery Shutdown

MDEQ Continues to Coordinate with EPA and City of Detroit following Marathon Refinery Shutdown

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 shutdown of the Marathon refinery in Detroit.

DEQ, City of Detroit, and EPA staff continue to meet with Marathon personnel at the refinery. The refinery has halted crude oil processing at the plant enabling them to reduce the volume of hydrocarbons to the coker flare system. This action has reduced the rotten egg odors being emitted from the refinery. 

The source of the odors created by the flare gas system are suspected to have been hydrogen sulfide and mercaptan compounds. Both of these compounds have extremely low odor thresholds meaning they can be smelled even at very low levels. Some people are more sensitive to these compounds than others and DEQ has received reports from the public that the strong odors coming from the refinery made them feel dizzy, out of breath, nauseous or caused headaches.

Apart from the odor, neither EPA’s or Marathon’s air quality sampling detected any exceedances of health thresholds during the event.  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. 

Marathon has attributed many of the problems the refinery faced last week to the extremely cold weather in the area and tells state and local officials that it is inspecting the plant for other freeze-related damage while planning repairs to the flare system.  Marathon has assured regulators and the City of Detroit that it will not begin processing crude oil at the plant until repairs are made to the flare and other safety systems at the refinery are operating properly. 

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