The Phillips 66 refinery is working to determine the source of an odor detected in the south Billings area Tuesday, according to the city.
The refinery was notified of the odor by the city and is conducting tests, according to a Phillips 66 statement.
Air-quality monitoring conducted inside and outside the refinery has so far indicated no harm to human health, according to the company.
Phillips 66 will provide updates on the situation on its community hotline at 406-255-2600.
