Thousands of air passengers are at risk from toxic fumes leaking into aircraft cabins, according to the Global Cabin Air Quality Executive pressure group.
There are fears that cabin crew and passengers are at risk
Some cabin air is drawn from the main engine and filtered - but oil vapours sometimes leak into the airstream.
The UK government says one in 2,000 flights is affected. Unions say it happens daily, causing nausea.
The group wants a public inquiry into why more has not been done to protect people and inform them of health risks.
In addition to nausea, the pressure group and pilots unions claim the leaks cause dizziness and lethargy.
They say passengers can also experience health problems but are not informed about the issue.
Their concerns stem from a process in which some of the cabin air that passengers and crew members breathe on a flight is drawn from the main engine and cooled.
The air is then mixed with re-circulated air. During the process filters remove bacteria but not oil vapours that could leak into the airstream if there are faulty seals in the engine.
The frequency of these leaks has been disputed.
The call for an inquiry has the support of transport workers union T&G, the Conservatives, Liberal Democrats and Green Party.
The T&G want all airlines to install onboard detectors and extra filters to protect passengers and crew.
The Department for Transport is now gathering samples from aircraft to establish what chemicals are present during flights.