Potential direct users of PFAS include metal plating facilities, paper manufacturing facilities, textile manufacturing facilities, electronic manufacturing facilities, and facilities that are known to have been contaminated with chlorinated volatile organic compounds (VOCs). Based on the type of site and historic operations, each of these potential PFAS direct users were assigned a risk score as previously reported by Guelfo et al., 2018 . Possible indicating scores are 100, 75, 50 and 25. These scores were also used in a study that performed statistical analysis to prioritize the sampling location for PFAS . On this scale, 100 represents the highest risk, indicating that the facility is highly likely to use or produce PFAS excessively. Sites with its upper magnitude, sources and indicating score are listed in Table .