An optional template for GreenScreen assessments is a "stratified" GreenScreen assessment. It allows the GS Profiler to provide hazard classification for a chemical based on exposure routes (oral, dermal, inhalation) for those hazard endpoints that may result in different hazard classification scores by exposure route. For example, carcinogenicity by inhalation can occur with some chemicals that are respirable but may not occur via the oral and dermal routes. The stratified GreenScreen is an important evolution for GreenScreen because it provides greater resolution and insight for the users of a GreenScreen assessment report. It is important to know if one particular exposure route is more hazardous than another. And it is important to know where there are data gaps for certain exposure routes - particularly when exposures are likely to occur via that route. For example, if a stratified GreenScreen assessment had been available for diacetyl, the chemical used in artificial butter in microwave popcorn, might it have been more obvious that the chemical is benign by the oral route but very hazardous via inhalation? Perhaps it could have helped to protect workers (and extreme microwave popcorn eaters!). A stratified GreenScreen helps to inform decision making. It would be a misuse of GreenScreen to selectively report results only for one exposure route. A conservative approach is to always report the highest hazard via any exposure route for any hazard endpoint. But it is better to stratify the GreenScreen hazard table so that more informed decisions can be made and important data gaps can be identified, especially when exposure can be anticipated.
