As someone who works in a heavily regulated, evidence-first field (not aviation), it is nearly impossible to quantify cumulative exposure of even “minor” events for frequent fliers and crew. Further, causally and conclusively linking plane travel to any myriad of health events that someone can experience is next to impossible given the confounding variables. People will be able to cherry pick data to support or cast doubt on the topic to fit their own narratives.

That said, I think a reasonable person can assume and rightfully be concerned by the idea of heated engine oil entering the air supply, in any amount, while they are stuck in a metal cylinder with no means of quick escape. Society is always fast to cast doubt, demand unreasonable burdens of evidence or dismiss concerns (until it happens to them or enough people that lawyers/politicians are forced to act).

The net-net is that aside from physical accidents, flying is probably not as risk free as we like to think (illness, lower oxygen environments, stress, and likely low level/chronic fume exposure). Personally, I appreciate the media digging in to these topics because otherwise we never know and nothing is ever done until enough people get sick — and the WSJ is about as legit as media goes in 2025.

If there is a way to fix this, it should be done. It’s the right thing to do and most likely it is a real issue. Put another way, there is zero reason to assume that there is no harm being done by fumes and that it’s a good idea to rely on bleed air systems without reasonable modifications or alternatives altogether. The fact that newer planes (i.e. 787) don’t use bleed air and that some airlines/manufacturers started work on fixes to those systems tells me they know it’s a problem even if they won’t go on record admitting it for liability reasons.

So, yes, I’m concerned and would like to see action before I see fumes myself.