Tom Cruise asked to use real nerve gas in which one of his movies?

It's hard to think of anything more Tom Cruise-ish than doing your own stunts — besides, maybe, demanding the use of real nerve gas on set.
Cruise is known for many things, in particular for his movies raking in over $11 billion at the global box office — but also a reputation for doing risky things in the name of cinema. We have to say, this one feels like taking things a step too far, even for good ol' Tom.
What movie had the actor asking for nerve gas?
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