[sq_]

Given that Starship and Super Heavy are both methalox fueled, wouldn’t the combustion products in the exhaust be carbon dioxide and water?

[verdverm]

Combustion is imperfect and it is occurring over metal which will erode into the mix of air and water. Then there is also whatever chemicals and material are on the ground prior to launch activities that get washed away with the deluge system

[FireBeyond]

> Then there is also whatever chemicals and material are on the ground prior to launch activities that get washed away

Washed away after first being superheated by that water.

[foobarqux]

Not according to the tests SpaceX submitted themselves. But if it were you would first show that to the EPA and then they would give you a permit to go ahead.