Narrative:

While the security & cleaning team were onboard doing their duties; the aft lavatory smoke alarm went off. Myself and the rest of the crew were in the fwd part of the cabin. A security team member came forward and asked us if we could turn off the loud alarm sound. The B flight attendant (flight attendant) went to the aft and notice it was the smoke alarm and inspected the lavatory and wasn't able to find the cause. The cabin started to get foggy and an electrical burn smell started to spread through the cabin. I informed the ca (captain) and he also witnessed the incident. He did his checks and turn off all power to the aircraft. The fire department was called and as they boarded their smoke detector they carry went off. We were instructed to remove our belongs and step into the jet bridge and we did as instructed. The fire department & maintenance weren't able to find the cause and signed off the plane as being good. The first officer (first officer) didn't feel comfortable flying the plane back as clearly there was a source that caused the smoke detector and electrical burn smell to spread through the cabin. Myself and the rest of the crew didn't feel comfortable on the plane for safety reasons. The pilot was talking to the [operations] noc on a station cellphone provided by the station personnel. We voiced our safety concerns and were told the plane was signed off good to go. We were threatened and told if we didn't work the flight back to fll we would be disciplined and given a trip assignment refusal. Our safety concerns were dismissed by the company and forced to fly. Myself and the B flight attendant had severe headache and the C flight attendant had discomfort in her eyes. We never said we were refusing to fly back to fll; we stated we didn't feel safe on the aircraft in question. The security team continued their checks as they weren't able to finish and we boarded. The security team or cleaners didn't sprayed anything in the cabin that would have caused the smoke alarm to go off or cause an electrical smoke event. During the flight back to fll the cabin was hot and didn't cool off. One of the flight attendant that took the same plane in fll also stated the plane never cooled off during her flight.

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Original NASA ASRS Text

Title: B737 flight attendants reported aft smoke alarm sounding with smoke and haze in cabin during preflight.

Narrative: While the security & cleaning team were onboard doing their duties; the AFT lavatory smoke alarm went off. Myself and the rest of the crew were in the FWD part of the cabin. A security team member came forward and asked us if we could turn off the loud alarm sound. The B FA (Flight Attendant) went to the aft and notice it was the smoke alarm and inspected the lavatory and wasn't able to find the cause. The cabin started to get foggy and an electrical burn smell started to spread through the cabin. I informed the CA (Captain) and he also witnessed the incident. He did his checks and turn off all power to the aircraft. The fire department was called and as they boarded their smoke detector they carry went off. We were instructed to remove our belongs and step into the jet bridge and we did as instructed. The fire department & Maintenance weren't able to find the cause and signed off the plane as being good. The FO (First Officer) didn't feel comfortable flying the plane back as clearly there was a source that caused the smoke detector and electrical burn smell to spread through the cabin. Myself and the rest of the crew didn't feel comfortable on the plane for safety reasons. The pilot was talking to the [Operations] NOC on a station cellphone provided by the station personnel. We voiced our safety concerns and were told the plane was signed off good to go. We were threatened and told if we didn't work the flight back to FLL we would be disciplined and given a trip assignment refusal. Our safety concerns were dismissed by the company and forced to fly. Myself and the B FA had severe headache and the C FA had discomfort in her eyes. We never said we were refusing to fly back to FLL; we stated we didn't feel safe on the aircraft in question. The security team continued their checks as they weren't able to finish and we boarded. The security team or cleaners didn't sprayed anything in the cabin that would have caused the smoke alarm to go off or cause an electrical smoke event. During the flight back to FLL the cabin was hot and didn't cool off. One of the FA that took the same plane in FLL also stated the plane never cooled off during her flight.

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.