Narrative:

Right after deplaning in ZZZ; a smell overcame the air duct system on the plane. I immediately went to R1 to open the door. I received fresh air very quickly. I also informed the first officer (first officer) about the violent odor and he shut down the air. He then went outside to find out what it was. The odor was like fiberglass burning or a plastic. Very powerful though. The 2 fas (flight attendants) in back could not escape the smell. The cleaners in back could not escape the smell. The a flight attendant who is also 20 weeks pregnant; could not escape the smell. After the other 3 fas got off the plane; maintenance came upstairs and apologized. They said it was the herman nelson (ground air/heater unit) that caused the smell. They were using it to try and unfreeze the water valve. The captain; first officer; and myself had all doors and the flight deck windows open for over 1/2 hr to try to get the smell out. The air was turned on again to try and clear the system. Yes; the odor lasted for at least a half hr. I was fortunate to always make sure I had fresh air during my stay on the plane. I did not leave the plane for any of the lengthy delay. The other 3 fas were released from the return flight home. I worked the return flight home. Same as previous version. My getting fresh air kept me from being affected.

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Original NASA ASRS Text

Title: B737-900 Flight Attendants reported a fume event shortly after arrival deplaning resulting in Flight Attendants experiencing physiological symptoms.

Narrative: Right after deplaning in ZZZ; a smell overcame the air duct system on the plane. I immediately went to R1 to open the door. I received fresh air very quickly. I also informed the FO (First Officer) about the violent odor and he shut down the air. He then went outside to find out what it was. The odor was like fiberglass burning or a plastic. Very powerful though. The 2 FAs (Flight Attendants) in back could not escape the smell. The cleaners in back could not escape the smell. The A FA who is also 20 weeks pregnant; could not escape the smell. After the other 3 FAs got off the plane; maintenance came upstairs and apologized. They said it was the Herman Nelson (Ground Air/Heater Unit) that caused the smell. They were using it to try and unfreeze the water valve. The Captain; FO; and myself had all doors and the flight deck windows open for over 1/2 hr to try to get the smell out. The air was turned on again to try and clear the system. Yes; the odor lasted for at least a half hr. I was fortunate to always make sure I had fresh air during my stay on the plane. I did not leave the plane for any of the lengthy delay. The other 3 FAs were released from the return flight home. I worked the return flight home. Same as previous version. My getting fresh air kept me from being affected.

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.