Date: 201909
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Workload
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Flight Attendant
When detected: Taxi
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: We took off without any issue. I was Pilot Flying; First Officer was Pilot Monitoring. The takeoff climb and cruise portion of the flight was uneventful. During the initial descent we encountered some light to moderate chop due to build up cumulonimbus clouds. We did our best to avoid them while coordinating with ATC. We were being vectored onto the approach for [Runway] XXL. Prior to configuring the airplane to land; ATC canceled our approach clearance. We were given a climb to 5;000 feet on a heading of 360. We were at flaps 20 and 170 kts at around 4;000 feet MSL. I put the airplane in a climb and brought the flaps back up and sped up to 200 kts. We were informed that Runway XXL was closed due to FOD on the runway and to expect vector to [Runway] XXC. We were vectored and cleared for the ILS XXC ZZZ. The approach and landing was uneventful. This resulted in a normal landing. As we decelerated; I transitioned to the tiller to make the high speed Taxiway XY. As I was clearing the runway and making a right hard turn onto Taxiway X; the aft Flight Attendant rang the EMER call button. I asked my First Officer to take the call while I simultaneously listened in and taxied. The aft Flight Attendant stated that the cabin was filling up with smoke. During the call; both the First Officer and I started smelling smoke/fumes. I advised ZZZ Tower that we had smoke in the cabin and that I was requesting emergency vehicles to meet us at the west hard stand.  I called the Flight Attendant and asked if they saw a fire. I asked for an organized deplaning of the aircraft using the forward air-stairs. Everyone deplaned onto the hardstands without any injuries or incidents. I instructed the First Officer to gather all the passengers on the hardstand and make sure everyone was safe. As soon as the passengers were fully deplaned; I walked up and down the airplane to make sure that everyone was off. The Firefighters were on the airplane as I made my way back up. The first Firefighter made the comment' Wow; this truly is a lot of smoke.' The firefighters check the airplane inside and out and were unable to find a fire. They checked multiple times but could not find the source of the smoke; but did mention that it smelled like an electrical fire. I personally thought it smelled like burning of a petroleum base product; maybe even like burning rubber. I called ZZZ operations to get a few buses to get the passengers off of the tarmac. I also called Maintenance Control to get Maintenance personnel out to the airplane. Then I called the Chief Pilot's office. Chief Pilot would later meet us up at the airplane.Detection occurred visually by the Flight Attendant; and through smell when it reached the flight deck. After it was all said and done; one of the Flight Attendant thought they heard a louder than normal 'popping sound' after one of the moderate chop encounters. I don't know if this played any into this situation.At this point in time; I'm not exactly sure what caused this to happen. When speaking to Maintenance and the Chief Pilot they asked me about having any caution messages related to the packs. I told them yes initially; but after further thought; part of the Smoke/Fumes/Fire checklist has you cycle the bleed source and cycle on and off the Packs. I'm not sure if this is what I recall seeing on the EICAS; or if was truly related to the smoke. On the initial call to the flight deck from the Flight Attendant's; we did not have any caution messages; and the status messages that we had were related to the three MEL's the airplane had. One of the mechanics asked about the right pack having something to do with it; but because it was MELed; it was off the whole time. We never turned it on.Appropriate Checklist were ran; and the passengers were deplaned using air stairs and subsequently taken to the terminal using Ops buses.Maybe adding a smoke/fire/fumes checklist for when on the ground or at least making it easier to get to.


Second narrative: Our approach was normal to Runway XXL when the Tower canceled the landing clearance and initiated a go-around with radar vectors out; around and back to [Runway] XXC. We [were] cleared to land. Upon landing and during the rollout; we heard a call button ding and I looked down to see the emergency button flashing and heard the subsequent dings. The Captain responded to the Flight Attendant who said there was smoke filling the cabin. The Captain called for the QRH and I pulled it out calling for the immediate action items: Don mask and crew communication (abbreviated here). As we were on the ground; I opened the QRH to run through a check list as the Captain steered the aircraft off the runway on. Called the Tower to let them know of the situation and to roll the trucks. As the Captain rolled toward the ramp; I contacted the Ramp Controller and let them know of the situation and that we were going to park in the handstand where they consented and we parked as quickly as possible. As we entered the ramp; I continued the QRH checklist and we began to shut down the aircraft and subsequent systems per the QRH. At which time we followed the QRH and deplaned. Once complete; the Captain moved to the cabin to assist the flight attendants and I went outside to help direct passengers away from the active ramp and taxiways. Emergency personnel arrived promptly and we followed their instructions. The flight attendants saw and smelt the smoke first; sounded the alarm and simultaneously we in the cockpit also smelt the smoke and the air began to form a haze.


Synopsis: CRJ-900 flight crew reported smoke in cabin and flight deck during taxi shortly after landing.