Oahu’s reopening metrics are so restrictive that even the return of only a few thousand tourists, might be enough to upset the fragile balance and keep the county from further economic reopening.

Oahu’s seven-day average case count is now at 82, the fifth straight day below 100, and the island’s seven-day positivity rate is at 3.3%. Keeping the average case count below 100 for 14 days and the average positive test rate below 5% for 14 days is what needs to happen to move to the next tier of economic reopening.

On Saturday, Honolulu Mayor Kirk Caldwell urged Oahu residents to continue the low coronavirus case counts to move from Tier 1 to Tier 2 of his reopening strategy. Caldwell said moving to the next tier could be a possibility in the third week of October if Oahu keeps it up.

But there’s not much room for error. If Hawaii Lt. Gov. Josh Green and Hawaii Pacific Health president and CEO Ray Vara are correct in their estimates, the reopening of tourism on Oct. 15 will lead to a 20% increase in COVID-19 cases, mostly from the return of residents.

To absorb a 20% increase of COVID-19 cases and keep the seven-day average of new cases below 100, Oahu must start with the average case count at 83 or below. In the last two weeks, Oahu has rarely been able to hit that goal.

Green has estimated that only about 1 in 1,000 visitors would be positive for COVID-19 since most will have been tested for COVID- 19 before they arrive. However, he said COVID-19 case counts are likely to increase with the reopening of businesses that serve the tourists and the return to work of hotel workers and other employees.

Oahu’s metrics are designed to keep COVID-19 from surging like it did after Memorial Day, a phenomenon that turned Hawaii from one of the nation’s safest destinations to a coronavirus hot spot.

Oahu’s phased economic reopening plan includes four tiers of progressively looser restrictions. The plan, which began Sept. 24, will keep Oahu in each tier for a minimum of four weeks. To move to the next, less restrictive tier, the target numbers — below 100 and 5% — must be maintained for the last two weeks of the four week period.

As it is, for their first six days at least, tourists on Oahu will find themselves under the island’s tightest level of restrictions, known as Tier 1, which limits indoor and outdoor gatherings, including luaus, to five people, keeps bars and nightclubs closed, and bans stays in legal vacation rentals.

Restaurant dining on Oahu in Tier 1 is restricted to groups of no more than five people who have to come from the same household. Helicopter tours are forbidden, although sky- diving in groups of five is allowed. Tour buses cannot operate unless the windows can roll down or they are open air trolleys, which aren’t allowed on freeways.

Cal Dorn, CEO of Paradise Helicopters, is among those who fear Oahu’s metrics mean that the county won’t get out of Tier 1 quickly, which doesn’t bode well for tourists or residents.

“It’s a dilemma. Nobody wants COVID-19 to get worse and will (tourists) bring it in, probably. But for us, we’re not increasing COVID-19 spread by what we are doing,” Dorn said.

Dorn said his company closed during the initial lockdowns and put in mitigating procedures when it was allowed to reopen briefly. Now Oahu’s helicopter industry is once again closed. Helicopters can operate on all the other counties, he said.

“We don’t accept single- seat bookings anymore. We normally sell six seats, but we are only doing five-seat buy-outs. No one sits next to the pilot, and we have a plastic barrier between the pilot and the passengers so they are not breathing on each other. We also can fly with the doors off for more air circulation,” Dorn said.

Dorn said Oahu’s reopening plan’s helicopter restrictions violate the principle that the federal government is in charge of air space. He said the county’s restrictions came without consulting the helicopter industry and seem arbitrary given that sky-diving operations, which typically are conducted in small planes, have been allowed to continue.

Ultimately, Dorn said the restrictions could have long lasting impacts.

“We’re down to about half of the people that we used to have. We got payroll protection program and aviation industry payroll support program. We’re trying to stretch that until tourism reopens, but I don’t think we’ll see anything substantial until 2021,” he said. “I don’t think we’ll get out of Tier 1 quickly either. Everyone has the same thought.”

The neighbor islands currently have fewer COVID-19 restrictions in place.

However, Gov. David Ige is still considering a request from Kauai Mayor Derek Kawakami to allow Kauai to require incoming travelers to quarantine for 72 hours and then take a second test to get out of the 14-day quarantine. Other neighbor island counties also could ask for greater restrictions than have been set for Oahu, where the bulk of COVID-19 cases have occurred.

On Sunday, Green defended the policy that visitors get one COVID-19 test prior to arrival rather than multiple tests.

Green, in a Facebook video message, said testing visitors a second time after they arrive, would decrease the number of cases to under one per thousand — but it’s not worth it.

“The idea of a second test which would take 8,000 tests for us rolling every day, when we only have 4,000, is problematic for many reasons,” he said. “One, it would be extremely high yield. It’d be doing that just to weed down five or 10 cases, instead of using tests on people who are close contacts, who really would spread the disease.”

Green said requiring an additional test would take twice the state’s daily supply of tests, and those tests would be better used for first responders, teachers, long-term care facility workers and other high- risk groups like Pacific Islanders.

Star-Advertiser reporter Andrew Gomes contributed to this story.