It is extremely destructive—hence the term “oxidation”. Engineers spend countless hours attempting to offset its effects on nearly anything they design & build. It costs billions of dollars per year to prevent its damaging effects, and at least ten times that to mitigate or repair its ravages.
Combined with relatively modest heat, it sustains combustion; the higher the concentration, the more violent the combustion, and the less heat it takes to begin.
There are documented cases of piles of old automobile tires spontaneously combusting just from the heat of reaction between the free oxygen present combining with the steel ‘cords’ in the tires, as they rust!
The toll of destroyed homes, businesses, and lost lives from free oxygen violently reacting with oily rags, just from the minuscule heat generated by the oil drying, is staggering!
Then there are underground coal seams that have spontaneous combusted due to the presence of —again!— OXYGEN, and have burned for decades; perhaps even centuries!
Between global warming, and any increase in free atmospheric oxygen, the entire earth will spontaneously combust!
It also is terribly inimical to life: The Oxygen Catastrophe nearly wiped out ALL life on Earth! It could happen again!
In moderately high concentrations, it leads to dehydration of lungs & mucous membranes, intoxication, and uncontrollable euphoria in man & animals; it even has deleterious effects on plants. At slightly higher concentrations, it leads to death of both plants and animals.
Oxygen is thus a dangerous (and, indeed, is so labeled when transported or stored!) unstable, and poisonous gas that must be closely monitored, controlled, and ultimately cleansed from the atmosphere.
When is the EPA going to do its job!?!
It might take me a while to get back to you.