Narrative:

While boarding; just before door closure; light visible smoke and a strong burning plastic odor was noted in the cabin. I notified the captain and confirmed the cabin was in fact filling with smoke. The captain instructed me that the passengers would need to deplane the aircraft and asked me to put him on the public address. While he was addressing the passengers; I noticed the yellow safety step had been removed from the main cabin stairs and was just a few feet away. I exited the aircraft and replaced the safety step. I got the attention of two nearby ground agents and informed them of the situation; instructing them to keep the passengers contained to the area around the aircraft nose and call for help. I re-entered the aircraft and began instructing the passengers to exit the aircraft without delay leaving their belongings behind. Approximately 10 passengers had exited the aircraft before I was able to re-board and continue my duties. All passengers deplaned without issue within approximately 90 seconds of the captain's instruction. Additional ground agents and supervisors were on the [scene] within minutes of the event. Maintenance and ZZZ airport fire responded promptly and [confirmed] the aircraft was not on fire and no further hazard existed to passengers or company [personnel]. Passengers were directed to return inside the airport while a plan was devised to reunite them with their belongings. [Flight] was operated on a different aircraft with the same crew after approximately 2 hour delay.I considered the missing safety step to be a serious and unnecessary hazard to expeditious deplaning and therefore made the discussion to get it back in position. We had several passengers with mobility issues and I knew the missing step would be a problem for them. In my opinion; the whole event was orderly; expeditious and safe. Ground [personnel] responded promptly and effectively. Supervisors are to be commended on their efforts to minimize passengers' inconvenience [and] maximize safety and order. My many thanks to them and the entire ZZZ ground crew involved in this event.

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Original NASA ASRS Text

Title: Dash 8 Series Flight Attendant reported smoke and burning plastic odor in cabin during boarding. The aircraft was deplaned.

Narrative: While boarding; just before door closure; light visible smoke and a strong burning plastic odor was noted in the cabin. I notified the Captain and confirmed the cabin was in fact filling with smoke. The Captain instructed me that the passengers would need to deplane the aircraft and asked me to put him on the public address. While he was addressing the passengers; I noticed the yellow safety step had been removed from the main cabin stairs and was just a few feet away. I exited the aircraft and replaced the safety step. I got the attention of two nearby ground agents and informed them of the situation; instructing them to keep the passengers contained to the area around the aircraft nose and call for help. I re-entered the aircraft and began instructing the passengers to exit the aircraft without delay leaving their belongings behind. Approximately 10 passengers had exited the aircraft before I was able to re-board and continue my duties. All passengers deplaned without issue within approximately 90 seconds of the Captain's instruction. Additional ground agents and supervisors were on the [scene] within minutes of the event. Maintenance and ZZZ Airport Fire responded promptly and [confirmed] the aircraft was not on fire and no further hazard existed to passengers or Company [personnel]. Passengers were directed to return inside the airport while a plan was devised to reunite them with their belongings. [Flight] was operated on a different aircraft with the same crew after approximately 2 hour delay.I considered the missing safety step to be a serious and unnecessary hazard to expeditious deplaning and therefore made the discussion to get it back in position. We had several passengers with mobility issues and I knew the missing step would be a problem for them. In my opinion; the whole event was orderly; expeditious and safe. Ground [personnel] responded promptly and effectively. Supervisors are to be commended on their efforts to minimize passengers' inconvenience [and] maximize safety and order. My many thanks to them and the entire ZZZ ground crew involved in this 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.