My understanding is that the ingredient that is the major suspect is tricreysl Phosphate.

I also believe the problem came to a head with the Bae146 which was powered by Four ALF502 engines.

John Warner selected the ALF502 because there was nothing around that could give the required performance with just Two engines.

Now the ALF502 started life as a Lycoming T55 Engine designed for the Chinook helicopter. They shoved a bloody great fan on its front end and pronounced it a turbofan. The trouble was that the front bearing arrangement for the new turbofan vibrated and also leaked oil - that went into the bleed air in quantity - or at least that is what I remember. Correct me if I'm wrong.

Not quite. Some of the air is from outside and some can be from inside the cabin. Hence RECIRC or in lay terms, recycled air. Just like on a bus, train, cinema etc. As mentioned above it is the OIL fumes that are the issue.

My understanding was that the contaminated air came from a dodgy seal on the gearbox? of the APU on the 146s. Bad/old/damaged seals allowed oil to pass through to and become heated (not burnt per se) so that the toxic component (tricresyl...) entered the bleed air.
There was a case on this a few years ago that was brought by a member of the cabin crew before the Dust Diseases Tribunal. If I remember rightly I think she was successful.
Scary stuff.

From AvWeb, USA.....4/2/2013

Remember this topic..??

"Deceased Pilots Claimed Aerotoxic Syndrome

The death of two former British Airways pilots, both 43 years of age, who both believed they were poisoned by breathing contaminated air in the cockpit of jets they flew may now lead to legal action. Shortly before his Dec. 12 death, pilot Richard Westgate reportedly instructed his lawyers to sue BA over his alleged poisoning. Pilot Karen Lysakowska was grounded with poor health in 2005 and developed lung cancer, passing away a few days after Westgate. Lawyers for Westgate are now pushing for an inquest into the pilot's death to prove the existence of "aerotoxic syndrome."

In 2007 a collection of flight crew members founded the Aerotoxic Association based on their experience with a range of chronic health issues that they attribute to contaminated cabin air, which they say ended their careers. They believe organophosphates in engine oil can enter the cabin as fumes delivered by bleed air systems. They attribute symptoms such as chronic fatigue, mood swings, loss of confidence and persistent headache to aerotoxic syndrome. Government-commissioned studies in the UK concluded in 2011 that cabin air was safe. Critics claim that toxic events occur on the order of roughly one per 100 flights and so may be difficult to detect without full-time air quality sensors. A spokesman for British Airways on the 27th told reporters it is not aware of any legal claims related to the deaths of the two pilots. Autopsy results are pending.

Sounds to me that these symptoms are very representative of shift work and dateline issues.

Forgive a Pom for butting in here, but there is a movement trying to raise awareness of the issue in the UK on R&N as you will have seen, triggered by the sad deaths of two relatively young BA pilots from cancer.

The 'Aerotoxic' website links to a fairly convincing analysis conducted in Aus into air toxicity in aircraft.

Does anyone here have any links to the subsequent actions (if any) that occurred down under?

I should stress that I am not trying to start any scare stories, wear a tinfoil hat etc, but seek only to make sure that a proper investigation takes place (which appears to be lacking in the UK), that crews are aware of the issue and to establish why BALPA appears for some reason to have completely forgotten how serious they said this was in 2005.

There was a case in NSW that was finally resolved in 2010 regarding "aerotoxicity" that occured in 1992.

Whether it exists or not, you're looking at a long hard slog to first get it recognised as your health complaint and then second to actually get some form of compensation. Unless you're critically ill after a fume event, I wouldn't be looking for a diagnosis, you'd just be pouring money down the drain at the moment.

Turner v Eastwest Airlines Limited [2009] NSWDDT 10 (5 May 2009)

Nomads as well
 

I was in the Army from the mid seventies to early eighties as an aircraft engineer/all trades with the last 3 years in a Porter/Nomad squadron. My job involved a lot of flying, maintaining the aircraft on exercises etc. It is pretty well known that early on the Nomad had a propensity to drain oil into the accessory gearbox then through the compressor and bleed air system into the cabin air. It was nothing to find 3-4 litres of oil on the tarmac, under the exhaust stacks. Because it had gotten into the bleed air it had to be purged out of the cabin air lines after start, filling the cockpit and cabin with burnt Mobil Jet II fumes. The whole of that period and for may years after I had to carry a nasal inhaler to clear my sinuses and suffered hours on end of headaches. I am sure that I am not the only one to experience this and I think there could be a stack more people that have suffered the health consequences of that initial design fault. Just putting that out there.