The U.S. Navy announced Monday that it has suspended use of World War II-era fuel tank farm above a Hawaii aquifer that supplies nearly 20% of Honolulu’s drinking water.

Navy Secretary Carlos Del Toro made the announcement during a briefing with reporters at Pearl Harbor after problems surfaced about two weeks ago on and near the base.

Nearly 1,000 military households have complained that their tap water smells like fuel and some have also complained that they have suffered physical ailments such as cramps and vomiting.

A water sample returned last week showed the presence of petroleum. The well is near the underground fuel tank complex that has been the source of multiple fuel leaks over the years.

Fuel from the tanks is used to power many U.S. military ships and planes that patrol the Pacific Ocean.

The announcement came after Hawaii’s governor and congressional delegation called on the Navy to suspend operations at the tank farm fuel tank farm that sits above an aquifer that supplies water to urban Honolulu.

Rear Admiral Blake Converse, deputy commander of the U.S. Pacific Fleet, said that the use of the tank farm was suspended on Nov. 27 but officials did not say why the Navy waited until Monday to make that announcement.

The Navy last week said a water sample from one of its wells showed the presence of petroleum. The well is near the underground fuel tank complex that has been the source of multiple fuel leaks over the years.

The Navy’s water system serves about 93,000 people. Nearly 1,000 military households complained about their tap water smelling like fuel or of ailments like stomach cramps and vomiting.

The Navy said it would flush clean water through the distribution system to clear residual petroleum products from the water. The process, along with testing, could take up to 10 days to make sure the water meets Environmental Protection Agency drinking standards.

The Navy also pledged to investigate how contaminates got into the well and to fix the problem.

The tap water problems have afflicted one of the military’s most important bases, home to submarines, ships and the commander of U.S. forces in the Indo-Pacific region. They also threaten to jeopardize one of Honolulu’s most important aquifers and water sources.

During World War II, the Roosevelt administration was concerned about the vulnerability of above-the-ground fuel tanks to attacks — so the Navy built the tank farm named the Red Hill Bulk Fuel Storage Facility.

The facility has 20 steel-lined underground tanks, which can collectively store up to 250 million gallons (946 million liters) of fuel. The tanks are encased in concrete and stored inside cavities of a volcanic mountain ridge near Honolulu. Pipelines from the tanks run 2.5 miles (4 kilometers) inside a tunnel to fueling piers at Pearl Harbor.

The fuel in the tanks is used by the U.S. Air Force, Army, Marines, Navy, Coast Guard and Hawaii National Guard for ships and aircraft. The Navy has said Red Hill is vital to maritime security, regional stability, humanitarian assistance and continued prosperity in the Indo-Asia-Pacific region.

The Department of Defense has spent more than $200 million on updating the facility and conducting environmental testing since 2006, according to the Navy.

(AP)