On 2023-10-27 at approximately 10:00 GMT, an Embraer ERJ-195LR aircraft was operating the first sector of its day flight from Exeter Airport, UK to Alicante Airport, Spain (BE4321). Both pilots reported experiencing a sweet-smelling odor after the APU and APU bleed had been turned on to heat the cabin. The odor was described as resembling caramel but was considered unusual given the aircraft?s initial start conditions. The aircraft proceeded to taxi and line up for takeoff, with daylight visibility exceeding 10 km and a wind of 210ø at 5 knots. The APU was shut down, and air conditioning packs remained active with engine supplied air. Subsequent to entering the runway, the aircraft experienced a different odor ? a faint paint-like and white spirit-like smell ? originating from the flight deck. The wind was behind the aircraft, prompting initial speculation of exhaust gas ingestion. Upon takeoff, the flight crew assessed the fumes and determined they were diminishing. The commander initiated the thrust levers to idle, and the aircraft remained on the brakes. The co-pilot subsequently observed worsening fumes and smoke entering the flight deck, leading to a rapid reduction of thrust. The commander then opened the flight deck windows to ventilate, and the co-pilot initiated an emergency evacuation. The evacuation process revealed smoke and fumes, with passengers experiencing difficulties exiting the wing. The commander contacted the SCCM, who reported smoke and fumes but could not identify the source. The commander instructed the co-pilot to initiate the engine bleed and air conditioning pack off. The aircraft’s engine indications remained normal. The co-pilot then retarded the thrust levers to idle, while still holding the aircraft on the brakes. Smoke intensified, and a puff of smoke entered the flight deck. The commander then set the park brake and requested the co-pilot to turn the engine bleed and air conditioning packs to off. The flight deck windows were opened to ventilate. The incident concluded with the co-pilot initiating the emergency evacuation, and the SCCM reporting the smoke and fumes. The investigation revealed an incorrect engine compressor wash procedure performed the previous night, potentially leading to the issue. EASA has initiated two safety actions related to over-wing emergency exits, and the operator has undertaken several safety actions regarding passenger safety briefings, maintenance planning, engineer training, competency and welfare, and ground equipment monitoring. Four Safety Recommendations are proposed to address over-wing exit markings and height requirements for assisted escape mechanisms.On 2023-10-27 at approximately 10:00 GMT, an Embraer ERJ-195LR aircraft was operating the first sector of its day flight from Exeter Airport, UK to Alicante Airport, Spain (BE4321). Both pilots reported experiencing a sweet-smelling odor after the APU and APU bleed had been turned on to heat the cabin. The odor was described as resembling caramel but was considered unusual given the aircraft?s initial start conditions. The aircraft proceeded to taxi and line up for takeoff, with daylight visibility exceeding 10 km and a wind of 210ø at 5 knots. The APU was shut down, and air conditioning packs remained active with engine supplied air. Subsequent to entering the runway, the aircraft experienced a different odor ? a faint paint-like and white spirit-like smell ? originating from the flight deck. The wind was behind the aircraft, prompting initial speculation of exhaust gas ingestion. Upon takeoff, the flight crew assessed the fumes and determined they were diminishing. The commander initiated the thrust levers to idle, and the aircraft remained on the brakes. The co-pilot subsequently observed worsening fumes and smoke entering the flight deck, leading to a rapid reduction of thrust. The commander then opened the flight deck windows to ventilate, and the co-pilot initiated an emergency evacuation. The evacuation process revealed smoke and fumes, with passengers experiencing difficulties exiting the wing. The commander contacted the SCCM, who reported smoke and fumes but could not identify the source. The commander instructed the co-pilot to initiate the engine bleed and air conditioning pack off. The aircraft’s engine indications remained normal. The co-pilot then retarded the thrust levers to idle, while still holding the aircraft on the brakes. Smoke intensified, and a puff of smoke entered the flight deck. The commander then set the park brake and requested the co-pilot to turn the engine bleed and air conditioning packs to off. The flight deck windows were opened to ventilate. The incident concluded with the co-pilot initiating the emergency evacuation, and the SCCM reporting the smoke and fumes. The investigation revealed an incorrect engine compressor wash procedure performed the previous night, potentially leading to the issue. EASA has initiated two safety actions related to over-wing emergency exits, and the operator has undertaken several safety actions regarding passenger safety briefings, maintenance planning, engineer training, competency and welfare, and ground equipment monitoring. Four Safety Recommendations are proposed to address over-wing exit markings and height requirements for assisted escape mechanisms.