Folks,
by the way: The important message that RJ Lee gave to Ron with their short reply was "There were freaking large fires, d'uh! Why would you think fires are not enought to put all sorts of stuff in the dust?". They present their opinion that ordinary fires are sufficient to explain everything. This renders RJ Lee witnesses against C7, who previously recuited RJ Lee as witnesses for his delusions. Everyone can see that, except, seemingly, C7.
However, on the science and the details, their story of hurricane winds ripping of the poor rusty steel is almost certainly nonsense.
It most probably nonsense to be talking about elemental iron and elemental lead. Much more probably, we are talking about all sorts of compounds of iron and lead. These compounds may have vastly different physical properties than the elements - such as lower melting and boiling points, or vapor pressures.
Lead is a stabilizer in PVC, making up as much as 2% by weight of that plastic. When PVC burns, the organics are turned into gas (HCl! Highly corrosive!), the lead remains in form of organic or inorganic compounds. Chlorides of various metals have boiling points easily within the reach of office fires. There were tons of PVC on each floor.
Folks, we really shouldn't be talking elements when in the heat of office fires chemistry produces millions of substances.
Does that mean RJ Lee is fundamentally wrong? Or incompetent? No. Fundamentally, they are saying that fire conditions were easily extreme enough to make vapors containg lead or spheres containing iron a very mundane thing indeed. I think they dumbed down their answer to a level they think appropriate for a layman like Ron, while at the same time managing their time economically.