In an All Operator Message, BAE Systems admits that oil gets into the cabins of their BAe 146 and Avro 146-RJ aircraft:

"The air supply is protected from contamination by seals, which achieve maximum efficiency during steady state operation, However, they may be less efficient during transients (engine acceleration and deceleration) or whilst the engine is still achieving an optimum operating temperature."

There then follows a comprehensive bullet-point list of items which crew can use in an attempt to reduce oil fumes in the cabin.

This is a clear admission that engine oil, which contains Tricresyl phosphate (TCP) routinely enters the aircraft cabin.

BAE Systems All Operator Message: Ref 00/030V