Narrative:

I was the pilot flying (PF); captain was pilot monitoring (pm). Immediately after rotation; we both noticed an odor in the cockpit that smelled like a mixture of burning electrical and burning oil/hydraulic fluid. Initially; we thought it may have been residual [de-ice]/anti ice fluid; as the aircraft was towed in from another location; (we had not accepted our first aircraft due to maintenance issues). We determined after a brief discussion that the aircraft had not needed deicing; and the smell must be coming from elsewhere. It was not dissipating.after cleanup and reaching a safe altitude; we briefly discussed the smell; which was not dissipating. I felt slightly light headed; and I was getting a dry; tingling feeling in the back of my throat. I recognized these from my military altitude chamber hypoxia symptoms; and informed [the] captain of my condition. As PF; I immediately donned my oxygen mask while [the] captain got into the QRH; ran the checklists; and tried to coordinate with flight attendants (flight attendant's) to see if they could smell the odor as well. The flight attendant's informed us that they could smell it; and it was getting more potent. [The] captain notified ATC of [our issue] and coordinated a return. After a few minutes; I was noticing the captain having difficulty with basic FMS functions and told him he should immediately don his mask; as I feared he was also experiencing signs of hypoxia. After donning his mask; he was able to return to normal; and we worked in tandem to get the aircraft turned around and back to the departure airport.I flew and talked on the radio; and the captain manipulated the FMS and checklists. We received a single frequency approach controller; and flew an ILS to the runway; with an overweight landing of approximately 163;000 lbs with a light touchdown and stopped on the runway while the emergency responding vehicles inspected our aircraft. Once given the all clear; we taxied back to the gate; remaining on oxygen the entire time until engines were shut down. We opened the flight deck windows for ventilation after we parked; and removed our masks. We were met at the aircraft by EMS; fire; and police first responders; who ran our vitals and transported us to the local emergency room. We were unable to pinpoint the cause of the fumes; but they persisted throughout the flight; approach; and landing. At this time; we do not know why this event occurred; where the fumes originated; or what could be done to minimize the risk. All hydraulic; oil; and bleed configurations and levels were normal.

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Original NASA ASRS Text

Title: B737 flight crew reported experiencing fumes in both the cockpit and cabin; which were nearly incapacitating; the flight safely returned to the departure airport.

Narrative: I was the Pilot Flying (PF); Captain was Pilot Monitoring (PM). Immediately after rotation; we both noticed an odor in the cockpit that smelled like a mixture of burning electrical and burning oil/hydraulic fluid. Initially; we thought it may have been residual [De-ice]/anti ice fluid; as the aircraft was towed in from another location; (we had not accepted our first aircraft due to maintenance issues). We determined after a brief discussion that the aircraft had not needed deicing; and the smell must be coming from elsewhere. It was not dissipating.After cleanup and reaching a safe altitude; we briefly discussed the smell; which was not dissipating. I felt slightly light headed; and I was getting a dry; tingling feeling in the back of my throat. I recognized these from my military altitude chamber hypoxia symptoms; and informed [the] Captain of my condition. As PF; I immediately donned my oxygen mask while [the] Captain got into the QRH; ran the checklists; and tried to coordinate with Flight attendants (FA's) to see if they could smell the odor as well. The FA's informed us that they could smell it; and it was getting more potent. [The] Captain Notified ATC of [our issue] and coordinated a return. After a few minutes; I was noticing the Captain having difficulty with basic FMS functions and told him he should immediately don his mask; as I feared he was also experiencing signs of hypoxia. After donning his mask; he was able to return to normal; and we worked in tandem to get the aircraft turned around and back to the departure airport.I flew and talked on the radio; and the Captain manipulated the FMS and checklists. We received a single frequency approach controller; and flew an ILS to the runway; with an overweight landing of approximately 163;000 lbs with a light touchdown and stopped on the runway while the emergency responding vehicles inspected our aircraft. Once given the all clear; we taxied back to the gate; remaining on oxygen the entire time until engines were shut down. We opened the flight deck windows for ventilation after we parked; and removed our masks. We were met at the aircraft by EMS; Fire; and Police first responders; who ran our vitals and transported us to the local Emergency Room. We were unable to pinpoint the cause of the fumes; but they persisted throughout the flight; approach; and landing. At this time; we do not know why this event occurred; where the fumes originated; or what could be done to minimize the risk. All hydraulic; oil; and bleed configurations and levels were normal.

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.