The medium through which an environmental exposure occurs (e.g., water, air, soil) is often geographically based and/or clustered. For this reason, responding to an environmental health threat in a meaningful and timely way requires real-time, granular data and prompt local action. The broad range of potentially relevant environmental health data sources highlights one of the key legal challenges with obtaining and using local data: often each type of data (hazard, exposure and health outcome) is governed by a different law and may be collected by a different entity.