The pilots' union, Balpa, last week asked its medical experts to study whether organophosphates (OPs) are responsible for complaints among airline staff which include dizziness, depression, headaches and loss of vision.
The move follows an Independent on Sunday investigation which revealed that 3,000 pilots and crew in America and Australia are claiming compensation for long-term damage to their nervous systems thought to have been caused by engine fumes leaking into the air on two types of plane, the British Aerospace 146 (pictured right) and the McDonnell-Douglas MD-80. One OP compound, Tricresylphosphate (TCP), is used in a Mobil oil to help prevent wear and tear of engines.
Bruce D'Ancey, assistant national secretary of Balpa, said: "There have been proven problems in farming with OPs and we need to see if it's a problem in aviation."
Six British cabin crew, represented by the Transport and General Workers' Union, are believed to be preparing legal claims for exposure to oil fumes. The TGWU has also asked airlines to monitor the air quality of the aircraft after a union survey showed 85 per cent of its 13,000 members were concerned about on-board fumes.
George Ryde, the TGWU national secretary for civil aviation, said: "I'm not certain airlines are conscious it's a problem for their crews. We don't have any firm evidence that fumes are coming through the fuselage and damaging health but we have to address this concern."
The Health and Safety Executive report on monitoring of exposure to organophosphorous pesticides concludes that repeated exposure at lower doses may cause "insidious cumulative toxicity", causing speech difficulties, memory loss, trembling and restricted use of limbs.
Last week, Paul Tyler, chairman of the all-party Parliamentary Group on OPs, submitted a written question to the Ministry of Defence asking for details of OP compounds in military aircraft. "The balance of risk is such that these products should no longer be used in any form," said Mr Tyler.
The pilots' study group is in contact with the Organophosphate Information Network, which has spent seven years providing counselling and advice for farmers suffering chronic neurological damage after using OPs in their sheep dip.
Dr Goran Jamal, senior lecturer in neuroscience at Imperial College London, and a former OP adviser to three government departments, said: "Given the high temperatures of engines when they operate it is likely that TCP will become airbound and, if there is a leak, will make its way quite easily into the airstream. It is extremely capable of getting absorbed efficiently via the skin or nose and eyes. It is then going straight into the bloodstream and your chances of limiting its toxicity are extremely limited."
Because it is being used as an "industrial lubricant", TCP does not have to be licensed for use as it would if it were being used as a "veterinary product". But it is still listed on the material safety data sheet for Mobil engine oil.
"The instructions say that if TCP is used according to the instructions it is perfectly safe," said Elizabeth Sigmund, co-ordinator of the OP Information Network. "But it's not the pilot's fault if there is something wrong with the engine system and the oil is being blown into the cabin. Somebody should have thought of this possibility. If the airlines are putting this stuff in planes you can't escape it. Inhalation is a powerful route of exposure and there's nothing else for the pilot to breathe."
A spokesman for Mobil said that TCP might be released under "extreme pressure" as the oil degraded". He added: "Our research suggests TCP may be neurotoxic if taken internally, but we don't believe it represents a significant health problem as a small part of vapour."
'I HAD A SEIZURE ON A FLIGHT FROM SINGAPORE TO FRANKFURT'
A PILOT on a leading airline says he had an on-board seizure a year ago which could be linked to engine fumes. He declined to give his name.
"I was flying from Singapore to Frankfurt. It was a long overnight flight and I was asleep in the first class section. I had a seizure at about 3am, convulsing and biting my tongue. They had to divert the flight to Calcutta, where I was taken to hospital.
"You can have seizures because of dehydration, sleep deprivation, hunger and stress. All those factors applied so I initially put it down to that. It was horrendous. Later, I heard dozens of other pilots had not reported their seizures for fear it would end their careers. If I've run into half a dozen pilots then you can imagine how many are out there. I've been told it will be another year or two before I'm allowed to go up again. They want to make sure it's not epilepsy. Thirteen neurosurgeons have given me a clean bill of health. But the cockpit crew get twice as much 'fresh' air as passengers. If something is leaking in then we're getting more of it more often than the passengers. Once or twice a year we smell engine oil on take-off - it isn't that unusual. But if we smell anything for more than a second or two we divert and land."Reuse content