In view of this other question, does the lead first enter or infiltrate the cabin air dispersion system, and then pervade or permeate the entire passenger cabin, thus every breathing passenger?

I believe that the recirculated cabin air passes through HEPA filters, but does this resolve all the menaces and perils of lead? If not, how can passengers protect themselves?

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    $\begingroup$ Note that most commercial passenger carrying aircraft are turbine powered and burn Jet-A, which does not contain lead. $\endgroup$
    – casey
    Jul 21, 2014 at 4:25
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    $\begingroup$ Well. to be totally pedantic here, some turboprops (say, with Garret engines) can burn avgas (with some restrictions) and do use `bleed air' which contains trace amounts of exhaust to heat the cabin. This is a very unlikely scenario, however. $\endgroup$
    – alexsh
    Jul 21, 2014 at 5:55
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    $\begingroup$ There is no exhaust in bleed air. It's taken from one of the compressor stages prior to combustion, there is no fuel and no exhaust in that air. $\endgroup$
    – Khantahr
    Jul 24, 2014 at 2:13
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    $\begingroup$ Passengers can best protect themselves by not drinking the fuel. (My doctor tells me this is generally good advice regardless of whether the fuel contains lead :) $\endgroup$
    – voretaq7
    Jul 25, 2014 at 19:55

1 Answer 1


Your question is based on an incomplete picture of how aircraft work, I'm afraid.

As a passenger on any major airline, the only lead you are likely to encounter is in the shielding on the security x-ray machines.

Fact: leaded fuel is relatively uncommon

First, tetraethyl lead is only present in what we call avgas - it is most often sold these days as 100LL (100-octane low-lead) aviation gasoline. Avgas is only used in piston (reciprocating piston) engines. Very few commercial aircraft in this day and age are powered by piston engines; most airliners are turbine-powered (jet or turboprop engines) and are fueled by Jet A, a variation on kerosene.

Fact: exhaust shouldn't be in the cabin anyway

Second, even if you happen to be flying in a light aircraft with a piston engine (or old, think Douglas DC-3 in Alaska), you shouldn't actually encounter any lead. The cabin air intakes are positioned intentionally to avoid any exhaust entering the cabin.

If exhaust carrying lead particles was reaching the cabin, you've probably got bigger and more immediate problems with carbon monoxide poisoning anyway.

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    $\begingroup$ Yep, this. CO is a far more immediate danger than lead. $\endgroup$ Jul 21, 2014 at 19:40

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