In accordance with these requirements, EPA's commitments underneath the PFAS Action Plan (USEPA, 2019a), and the approach described in this document, EPA is proposing checking for the unregulated contaminants mentioned in Exhibit three making use of the specified strategies. EPA has used an Assessment Monitoring tier for seventy two contaminants and contaminant groups about the course of UCMR one as a result of UCMR four.