A multimillion-dollar cleanup is on tap for Guam’s water system, after a toxic chemical banned for decades turned up in several wells.

The Consolidated Commission on Utilities has approved a contract worth up to $7.14 million to tackle dieldrin contamination, an insecticide linked to cancer and liver damage. 

Three wells: Y-15 in Yigo, D-17 in Dededo, and M-4 in Mangilao showed levels exceeding federal safety limits. 

One of them, near Andersen Air Force Base, tested eight times higher than what's considered safe. Guam Waterworks plans to install high-grade carbon filters to clean the water and refurbish two other sites as a precaution.

Only one company bid on the job, and at a steep price, 27% above estimates, but time is critical.

Funding will come from a federal grant, though GWA may dip into a $250 million bond if needed.

Cleanup crews have one year to finish. Meanwhile, officials stress this type of contamination is rare on Guam.