The Guam Environmental Protection Agency has lifted its “Do Not Drink Without Treatment” advisory for dieldrin contamination at Guam Waterworks Authority Production Well Y-15 after four consecutive weeks of sampling showed no detectable levels of the banned pesticide. The announcement follows GWA’s installation of an interim treatment system, which officials say has made the water safe for drinking, cooking, and all household uses.
“Clean and safe water is not just vital for health, but also crucial for residents’ peace of mind,” Guam EPA Administrator Michelle Lastimoza said. The agency will require monthly water sampling moving forward and has directed GWA to provide operating procedures for both interim and pending permanent treatment systems, along with documentation on the disposal of waste generated by them. Guam EPA is also revising its interim action level risk assessment for dieldrin and plans to seek public comment on updated response protocols.
Guam Delegate James Moylan announced that the U.S. Environmental Protection Agency has formally responded to his request for federal assistance. EPA confirmed that recent actions by GWA, Guam EPA, and the governor’s office have successfully brought dieldrin levels below detectable limits. The federal agency praised local authorities for issuing timely advisories, supplying alternative water sources, and installing treatment measures.
Moylan said the progress is encouraging but emphasized that long-term accountability remains essential. “EPA’s confirmation is welcome news, but this matter is far from over,” he said, adding that families deserve transparency about how the contamination occurred. EPA reported that long-term treatment equipment is funded and expected to be installed soon, and its Superfund program has requested that Joint Region Marianas investigate possible contamination sources at Andersen Air Force Base. Moylan said his office will continue coordinating with local and federal agencies to ensure Yigo residents remain informed as the investigation continues.