The Hawaii Department of Health gave residents of a second military neighborhood the all-clear to return to their homes, declaring Wednesday that water in the Pearl City Peninsula neighborhood is again safe to drink after fuel from Navy tanks contaminated the water supply.

The approval follows a monthslong flushing process in which Navy crews drained neighborhood water mains and household pipes of tainted fluid. Laboratories then tested water from approximately 10% of homes in each zone for lingering contaminants.

Some residents, however, have expressed doubts that testing one in 10 homes is enough to ensure all water is safe to drink.

Pearl City Peninsula, labeled Zone A1 on the Interagency Drinking Water System Team’s flushing map, is home to 635 households on the northwest end of Pearl Harbor.

“All of the 83 samples collected from homes or buildings in Zone A1 did not detect petroleum,” the Hawaii DOH wrote in a press release.

The Pearl City Peninsula neighborhood was, at one point, the first scheduled to be cleared, with residents slated to return late January. Residents of Red Hill Housing, a small neighborhood of 135 homes close to the Navy’s World War II-era fuel facility, became the first to return, with the Hawaii DOH giving the green light Feb. 14.

In all, the contamination crisis has affected some 9,600 households.

Fuel leaks from the facility contaminated a drinking well that supplied water to around 93,000 people, with 4,000 families choosing to live outside their homes since early-December, according to the Navy. Military neighborhoods have been unhooked from the affected well and are now getting their water from the Waiawa Shaft in Pearl City.