Pure oxygen is quite reactive, but in the grand scheme of industrial chemicals it is relatively benign. You could just mix it with outside air using a big fan,

Pure oxygen is quite reactive, but in the grand scheme of industrial chemicals it is relatively benign. You could just mix it with outside air using a big fan, if there are no better uses found for it. Oxygen has a huge amount of industrial uses though, so depending on the purity it might even be worthwhile to capture the waste stream and sell it.