Is it possible to set the environment settings at the tool level versus for the entire geoprocessor in ArcObjects? This can obviously be done for specific tools run via ArcToolbox and Model builder, but I can't find any examples of it being done at the tool level in ArcObjects when using ESRI.ArcGIS.Geoprocessor.Geoprocessor or ESRI.ArcGIS.Geoprocessing.GeoProcessor.
I don't think you can set an environment setting for a specific tool. I have found no methods that allow this. Environment settings are set at the geoprocessor level which calls the geoprocessing tool. This page shows you how to set/reset these.