Narrative:

Prior to pushback with the cabin door closed; we received a 'red smoke forward lavatory warning EICAS' message. Within a few seconds; we could smell smoke in the cockpit and since the tug was already hooked up and we were in communication with the driver; I let him know what was happening and confirmed that we told him we have a smoke warning in the forward lavatory and said he would contact arff for us. I left my seat and opened the cockpit door to check the forward lavatory. The smoke was not only more pronounced; but also visibly present. Not long after opening the door to the lavatory; the smoke alarm soon stopped. I would say this happened within 10 seconds. I had the first officer bring the cockpit fire extinguisher to me and I checked the toilet and the trash receptacle for a source of the smoke -- none was present. There also was no more smoke being produced. I had the first officer open the cabin door and then had him stand by the lavatory with the extinguisher as a precaution. I went outside the aircraft to see if I could see any signs or indications of a problem in the forward cargo area and also on the right side of the airplane where the lavatory service door areas were. I saw no signs or indications that a fire was or had been present. There was no smell of smoke either. I did not evacuation or deplane the passengers as all seemed under control and I did not want anyone to be in the way when the fire department personnel arrived. The mechanic arrived first and I told him what had happened and he began to do an inspection of the lavatory. I went back up to the cockpit and called our dispatcher to tell him what happened and to connect me over to maintenance control to fill them in and give them a 'job control number' with a write-up. The fire department arrived and did their checks with a heat scanner and said they had no signs of a fire being present and that everything around the lavatory area was either storage or an area that would not start a fire. The mechanic told me that it had to be the huffer cart as the source; and not the airplane. I had not heard of this before; but he did say along with some other personnel that it has happened before and quite common on air carrier's CRJ200's. Soon after; I had a call from the flight manager and I explained what was going on and what had happened and the actions I took. I did ask the mechanic and the fire officials to do an inspection -- both on the inside and the outside -- so that there would be no doubt about the safety of the airplane. After conferring with the director of flight operations; arff; soc; the mechanic and convinced there was no fire aboard the aircraft; we pushed out and flew to ZZZ. All paperwork was taken care of and the discrepancy noted in the log was signed off by the mechanic. Huffer cart used to start aircraft might have vaporized some deice fluid in the aircraft air conditioning system.

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Original NASA ASRS Text

Title: CRJ900 Captain reports 'smoke forward lavatory' EICAS message at the gate prior to push back. Smoke is visually confirmed but quickly dissipates.

Narrative: Prior to pushback with the cabin door closed; we received a 'Red Smoke Forward Lavatory Warning EICAS' message. Within a few seconds; we could smell smoke in the cockpit and since the tug was already hooked up and we were in communication with the driver; I let him know what was happening and confirmed that we told him we have a smoke warning in the forward lavatory and said he would contact ARFF for us. I left my seat and opened the cockpit door to check the forward lavatory. The smoke was not only more pronounced; but also visibly present. Not long after opening the door to the lavatory; the smoke alarm soon stopped. I would say this happened within 10 seconds. I had the First Officer bring the cockpit fire extinguisher to me and I checked the toilet and the trash receptacle for a source of the smoke -- none was present. There also was no more smoke being produced. I had the First Officer open the cabin door and then had him stand by the lavatory with the extinguisher as a precaution. I went outside the aircraft to see if I could see any signs or indications of a problem in the forward cargo area and also on the right side of the airplane where the lavatory service door areas were. I saw no signs or indications that a fire was or had been present. There was no smell of smoke either. I did not evacuation or deplane the passengers as all seemed under control and I did not want anyone to be in the way when the Fire Department personnel arrived. The Mechanic arrived first and I told him what had happened and he began to do an inspection of the lavatory. I went back up to the cockpit and called our Dispatcher to tell him what happened and to connect me over to Maintenance Control to fill them in and give them a 'Job Control Number' with a write-up. The Fire Department arrived and did their checks with a heat scanner and said they had no signs of a fire being present and that everything around the lavatory area was either storage or an area that would not start a fire. The Mechanic told me that it had to be the Huffer Cart as the source; and not the airplane. I had not heard of this before; but he did say along with some other personnel that it has happened before and quite common on air carrier's CRJ200's. Soon after; I had a call from the Flight Manager and I explained what was going on and what had happened and the actions I took. I did ask the Mechanic and the Fire Officials to do an inspection -- both on the inside and the outside -- so that there would be no doubt about the safety of the airplane. After conferring with the Director of Flight Operations; ARFF; SOC; the Mechanic and convinced there was no fire aboard the aircraft; we pushed out and flew to ZZZ. All paperwork was taken care of and the discrepancy noted in the log was signed off by the Mechanic. Huffer Cart used to start aircraft might have vaporized some deice fluid in the aircraft air conditioning system.

Data retrieved from NASA's ASRS site as of April 2012 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.