The crew was immediately given approval to shut the suspect system down. About thirty minutes after the crew first reported the smell, flight controllers asked the crew to close the interior hatch of the airlock to prevent the odor from further spreading through the station. Controllers then shut down some of the station's ventilation fans and powered on a system in the Destiny Laboratory to cleanse the station's atmosphere of any trace contaminants.
Flight controllers suspect the odor was caused by outgassing from a system that bakes metal oxide canisters to cleanse them of carbon dioxide. The canisters are used in U.S. spacesuits to cleanse the suit's atmosphere of carbon dioxide and can be recycled using the Quest airlock system. Some crew members did report briefly experiencing a slight headache that could have been a result of exposure to the odor. However, any symptoms quickly cleared and flight surgeons have initially determined that the odor, although unpleasant, did not pose any health problem for the crew.
The crew first reported the odor just after 4 p.m. CST. The interior Quest airlock hatch was closed at about 4:30 p.m. CST, and the crew began their sleep period at about 5:30 p.m. CST. Because of the slight lingering odor in the U.S. segment of the station, all crew members were expected to sleep in the Zvezda living quarters module tonight.