I don't know what material caused this, but I do know that it was not gas or diesel. If it were gas or diesel, the area would be completely dead. I know it happened Tuesday during the day because we watered the greens heavy that night explaining the runoff look. At the end of the day, it doesn't really matter how it happened, but rather what we are doing about it. Currently and fortunately there is a lot of green grass in the brown area so I think we should be fine in a matter of a week or so. If the area digresses, we will then have to sod which I am not hoping for.