perchlorate
EPA fails to regulate perchlorate (ClO4-)
https://www.epa.gov/sdwa/perchlorate-drinking-water https://www.epa.gov/newsreleases/epa-issues-final-action-perchlorate-drinking-water
https://www.epa.gov/sdwa/perchlorate-drinking-water https://www.epa.gov/newsreleases/epa-issues-final-action-perchlorate-drinking-water