Date: 201602
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Snow
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Time Pressure; Distraction; Confusion
Second reporter function: First Officer; Pilot Flying
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action; General Maintenance Action
Contributing factors: Aircraft; Chart Or Publication; Procedure; Weather
Primary problem: Procedure

Narrative: Upon departing; we deiced with the APU running and taxied out to the runway with high overcast skies. The light snow had stopped and the runways were clear. We were cleared for takeoff with a left turn to 160. Upon climb out through 200 to 300 feet I noticed a smell and white smoke started pouring out of the side vents. We quickly ran our Cabin Smoke Memory items and then ZZZ tower was calling us to make the turn that had been assigned to us. At the same time; the FA started calling us to advise us of smoke in the cabin. We went back to basics of Aviate; Navigate; Communicate and we went through the normal callouts through our masks to get the gear and flaps up and do the after takeoff configuration. I responded to tower that we [had] smoke in the cockpit that our plan was to air return and to please stand by. We backed up our memory items with the QRH and took ATC's request to turn left to 160 as the FO asked for autopilot to reduce the workload. Then ATC switched us to departure. He requested our FOB and Souls aboard. I asked him to stand by. We completed the after takeoff checklist and got started on the QRH. We completed the Cabin Smoke QRH and then called back to the FA. The FA said there was smoke in the cabin and we confirmed that we had it in the cockpit too. I gave the FA a quick briefing saying that we also had smoke in the cockpit that we were already getting vectors to come back to land at ZZZ. I stated that we would be on the ground in less than 10 minutes and I did not expect an evacuation of the jet and that we would taxi back to a gate and deplane there.After we had talked to the FA; I got back with the controller to give him Souls on Board and Fuel aboard. I also requested that they roll the trucks. At this point I went heads down to reconfigure the ACARS for the diversion and get landing data but the ACARS was giving me trouble in requesting landing data back to ZZZ even though we had changed the destination back to the departure airport. We were cleared down to 3000; given a final vector and cleared for the ILS. I decided that it was safer to come back heads up to focus on the flight and back up the FO instead of trying to get numbers from ACARS and flipping pages in the [FMS] to get the weights manually. I verbalized that the ACARS wasn't cooperating and that I didn't have time to get the landing numbers in from the [FMS] but I checked the landing weight and that we would be landing about 100lbs overweight. The FO acknowledged and stated he would fly above the white arc and aim for a very smooth landing. We landed normally and came to a stop after clearing the runway. We completed the after landing and called the FA to remind them to remain seated. By this time we had been handed off to a ground frequency and were talking to the fire trucks in front of us. The smoke had dissipated completely with only a lingering odor. We expressed our intentions to the fire crews that we were going to head back to the gate and deplane there but first they requested to walk around and look for anything obviously wrong. We confirmed and indicated to them that we had no heat or fire indications and the only thing we had seen was smoke. While the fire trucks inspected the jet; I made a passenger announcement; stating that we had had some smoke in the cockpit which could have been deice fluid burning in the A/C units but that we were not sure. I stated the firetrucks were doing an exterior inspection and when they gave us the green light; we were going to taxi back to the gate and deplane the aircraft. I further stated that we would keep them in the loop when we learned more about the status of the flight. The fire department escorted us back to the gate that [company] had assigned us and we deplaned the aircraft. The fire crew came on to look for signs of fire and said that they found none. After we completed all normal checklists; we called maintenance and wrote up smoke in the cockpit; low O2 from the oxygen that wehad used and overweight landing and we left the jet with the Maintenance crew.One major threat was the state of flight when the smoke event occurred. It was immediately after takeoff in a high traffic environment. If I had known that the smoke was going to stop fogging the cockpit and eventually dissipate I think an error that I committed was not asking for a few more vectors so that we had more time to finish inputting the landing data. However; as the source of smoke was unknown to us; I felt an urgency to get back on the ground as quickly and safely as possible. In the future I will be a little more thorough in my per-departure brief about air return weights and whether or not we will be overweight if we have to do an air return. I realized as we were coming back that I wasn't sure if we were going to be overweight until I checked the performance page and that surprised me. I also wish I had remembered to make the turn to 160 but the smoke really surprised me. Finally; I don't know if there was a connection between the APU running and smoke getting into the packs but in the future I am going to take the recommendation of deicing with an engine running and the APU down as a hard rule.


Second narrative: [Report narrative contained no additional information.]


Synopsis: EMB-145 crew deiced at the gate with the APU running. Immediately after takeoff; the cabin and cockpit filled with smoke and the flight returned to the departure airport. Deice fluid was suspected as the smoke's source.