A Honolulu Fire Department firefighter who was infected by the new coronavirus may have transmitted the disease to another firefighter at the Kalihi Uka firehouse while he was still asymptomatic, a city official said Thursday.

Dr. Jill Omori, the city’s infectious-disease officer, said there has been more information recently about asymptomatic people being able to transmit the virus.

“It’s thought that even though the first firefighter went to work when he was asymptomatic, that was probably within 24 to 48 hours before he started becoming symptomatic, and so it was enough time for them to have exposure to the other firefighters in that same unit,” Omori said during a phone-in news conference with reporters held with Mayor Kirk Caldwell and HFD Chief Manuel Neves.

Omori said the first firefighter who tested positive went to work after returning from his vacation but stayed at home after beginning to feel symptoms.

On Saturday the department said the first firefighter contracted the virus while on personal leave and that HFD did not think anyone else had been exposed.

Neves said Thursday that firefighters exposed to two colleagues at the Kalihi Uka firehouse who tested positive for the coronavirus have been ordered to stay at home and self-isolate for 14 days but have not themselves necessarily been tested.

Omori said testing is being conducted only for those showing symptoms, as has generally been recommended.

“Just because you’re exposed to somebody (who tested positive) and even if you are going to at some point become positive, we don’t test during the asymptomatic period because the viral load isn’t high enough to detect it, and so even if you get a negative test … it’s like a false sense of security because that doesn’t necessarily mean they’re negative.”

The Kalihi Uka station closed Tuesday to be cleaned and disinfected after the second firefighter there tested positive.

Firefighters from nearby stations responded to Kalihi Uka’s calls during the closure period, and firefighters from elsewhere are filling the shift of those sidelined because they are in self-isolation.

Neves said about a dozen firefighters have been tested for the coronavirus, but there is no mandate for those at the station or the department to do so.

The department already has a standard guideline for disinfecting and sanitizing fire stations, he said, but the department in recent days obtained five pieces of equipment that provide an electrostatic method of cleaning the fire stations and firetrucks. Oahu Transit Services, which operates TheBus and TheHandivan, has been deploying electrostatic cleaning methods for several weeks.

All 43 stations are expected to be cleaned in this method in the coming days, Neves said.

The department has enough personal protective equipment to deal with current needs, but “if the use explodes to an unbelievable amount, then we may not have,” the chief said.

Also announced at Caldwell’s news conference:

>> The city and Maui and Kauai counties were told by the White House that it has received their request to have President Trump suspend all air travel between Hawaii and elsewhere, and would need to hear from Gov. David Ige before making a decision, Caldwell said. Ige spokeswoman Jodi Leong said the governor had not yet seen any correspondence from the White House on the matter. “We continue to study the unintended consequences of halting all non-essential domestic travel to Hawaii,” Leong said.

>> The mayor said all Oahu residents should now be wearing homemade masks when they travel outside their houses. Kuakini Medical Center emergency room Dr. Darragh O’Carroll said up to 20% of those infected don’t show any symptoms so could be spreading the virus to others.

>> The mayor urged the public to report cases of businesses that are operating outside of the stay-at-home/work-from-home order to the city at 768-CITY. “We’re getting more and more calls now about people complaining about businesses that are open and are not essential and should be closed.” If the businesses persist, they will be visited by Honolulu police, he said.

>> The annual Memorial Day service scheduled for May 25 at the National Memorial Cemetery of the Pacific at Punchbowl is canceled.