Narrative:

During an idle descent passing thru approximately 14;000 ft the first officer asked if I smelled anything unusual. At first I did not notice anything. Then a minute later I commented on a musty smell. It did not seem significant at that time; then the first officer commented that she thought it was getting worse. I could now smell what she did; kind of like a light maintenance oily garage smell. At about 9;000 ft I called the cabin and asked if there were any odors or fumes in the cabin. The answer was negative. There were no vapors or smoke and aircraft systems indicated everything normal. I did not realize that the fumes were concentrated at the first officer position on the flight deck. With only about 10 minutes to landing and on an intercept to localizer I elected to focus on the approach and landing. At this point I still did not think the event was significant. After landing during taxi to the gate the fumes were noticeably stronger and the first officer requested to open her window for some fresh air. Maintenance was called out and after doing the parking checklist I debriefed the mechanic and filled out the [maintenance log]. At this time I started to notice an oily taste in my mouth. Departing the jet bridge the first officer commented that she did not feel right and we decided to call [my union] for guidance. While filling out the smoke; odor; and fumes report form I began to have symptoms similar to the first officer. The oily taste; nasal and throat irritation along with a slight headache. We decided to call off the trip and seek medical for a checkup. [Operations control] along with the [maintenance control] were notified. We were seen at the urgent care [in the airport]. We both had elevated blood pressure and elevated levels of carbon monoxide. Chest x-rays were taken. After treatment of 30 minutes on oxygen another blood draw was accomplished and co (carbon monoxide) levels had come down. We were released and deadheaded home. [Operations control]; tracking/scheduling; chief pilot were notified. I checked the aircraft maintenance log this morning. It looked like it turned out to be an electronic equipment cooling fan failure.

Related reports:

Google
 

Original NASA ASRS Text

Title: B737-800 flight crew reported smelling odors in the cockpit during the descent. Upon landing the crew was found to have elevated levels of carbon monoxide in their blood.

Narrative: During an idle descent passing thru approximately 14;000 ft the First Officer asked if I smelled anything unusual. At first I did not notice anything. Then a minute later I commented on a musty smell. It did not seem significant at that time; then the First Officer commented that she thought it was getting worse. I could now smell what she did; kind of like a light maintenance oily garage smell. At about 9;000 ft I called the cabin and asked if there were any odors or fumes in the cabin. The answer was negative. There were no vapors or smoke and aircraft systems indicated everything normal. I did not realize that the fumes were concentrated at the First Officer position on the Flight Deck. With only about 10 minutes to landing and on an intercept to Localizer I elected to focus on the approach and landing. At this point I still did not think the event was significant. After landing during taxi to the gate the fumes were noticeably stronger and the First Officer requested to open her window for some fresh air. Maintenance was called out and after doing the parking checklist I debriefed the mechanic and filled out the [maintenance log]. At this time I started to notice an oily taste in my mouth. Departing the jet bridge the First Officer commented that she did not feel right and we decided to call [my union] for guidance. While filling out the Smoke; Odor; and Fumes Report form I began to have symptoms similar to the First Officer. The oily taste; nasal and throat irritation along with a slight headache. We decided to call off the trip and seek medical for a checkup. [Operations Control] along with the [Maintenance Control] were notified. We were seen at the Urgent Care [in the airport]. We both had elevated blood pressure and elevated levels of Carbon Monoxide. Chest X-rays were taken. After treatment of 30 minutes on Oxygen another Blood Draw was accomplished and CO (Carbon Monoxide) levels had come down. We were released and deadheaded home. [Operations Control]; tracking/scheduling; Chief Pilot were notified. I checked the Aircraft Maintenance Log this morning. It looked like it turned out to be an Electronic Equipment Cooling Fan failure.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.