Detroit Marathon Oil Refinery repairs could last into next week

DETROIT – The ongoing problem with the Marathon Oil Refinery in Southwest Detroit could continue into a second week.

ORIGINAL STORY: Marathon confirms foul gas odor is from its Detroit refinery

Marathon determined the source of the odor was a flare at the refinery that was not functioning properly.

Repairs started Friday that have the potential to release more odors into the air, according to city officials. The scent comes from hydrogen sulfide and mercaptan.

The Michigan Department of Environmental Quality said the frequent air purity tests have come back clean of toxins, but the scent could cause those sensitive to odors to have headaches, nausea, vomiting or even difficulty breathing. 

RELATED: Residents with sensitivity to smell encouraged to stay inside as Detroit Marathon completes repairs

MDEQ advises residents to keep their windows closed.