Narrative:

We departed climbing up to 2000 feet on a heading of 090. While passing through 1000 feet; pilot flying said he was feeling dizzy; light headed; nauseous and repeated 'I feel weird; how do you feel?' after he asked me; he stated 'your controls'; so I am now flying the plane. I started to feel the effects of of lightheaded and a 'drunk like' feeling. As soon as I felt the effects; a portable ads-B device with a co detector alarm came on alarming us of co levels (80-95 ppm). I then made the decision to [notify ATC] and return back to the airport. While making a short approach to the other pilot's symptoms appeared to worsen so I was fully in control of flying the aircraft. Tower cleared the traffic and we landed. As soon as we landed we immediately opened the doors. I began to feel better immediately and the other pilot continued to improve. By the time we got back after seeing multiple doctors; over 9 hours had passed so they were unable to do carbon monoxide test due to the time lapses from the event.

Google
 

Original NASA ASRS Text

Title: An instructor pilot reported both pilots experienced carbon monoxide poisoning and returned to the airport and landed.

Narrative: We departed climbing up to 2000 feet on a heading of 090. While passing through 1000 feet; pilot flying said he was feeling dizzy; light headed; nauseous and repeated 'I feel weird; how do you feel?' After he asked me; he stated 'your controls'; so I am now flying the plane. I started to feel the effects of of lightheaded and a 'drunk like' feeling. As soon as I felt the effects; a portable ADS-B device with a CO detector alarm came on alarming us of CO levels (80-95 ppm). I then made the decision to [notify ATC] and return back to the airport. While making a short approach to the other pilot's symptoms appeared to worsen so I was fully in control of flying the aircraft. Tower cleared the traffic and we landed. As soon as we landed we immediately opened the doors. I began to feel better immediately and the other pilot continued to improve. By the time we got back after seeing multiple doctors; over 9 hours had passed so they were unable to do Carbon Monoxide test due to the time lapses from the event.

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.