Unite, Britain’s biggest trade union, is providing funding for current and former flight staff so they can take legal action against British airlines.
17 former and serving cabin crew, all of whom believe they have fallen ill from inhaling contaminated cabin air, are taking legal steps against British airlines in the civil courts.
The workers involved are claiming that engine oil and other toxic chemicals were circulated as part of aircraft air supplies.
Incidents where either smoke or fumes are released into aircraft cabins are rare, according to the Civil Aviation Authority (CAA), and there is no evidence of any long-term health effects following exposure.
However, safety reports submitted to the CAA show that between April and May 2014 there were 251 separate reported instances of fumes or smoke leaking inside a large passenger jet operated by a British airline.
An illness was reported in 104 of the 251 cases, and oxygen was supplied on at least 28 of the affected flights.
Unite has called for a public inquiry into contaminated cabin air.
Approximately half the air on board a flight in a modern commercial jet is drawn in through the engines.
As a result of this, campaigners claim that if engine seals leak it can lead to potentially poisonous gases reaching the cabin.
Some cabin crew members believe that these events, in addition to exposure to low levels of chemicals over many years, can be linked to damaging their long-term health.