Mayor Kirk Caldwell, who last week issued an executive order instructing Oahu residents to stay away from those not in their immediate family, on Wednesday sent a memo to about 10,000 city employees urging them to not gather for lunch or other social occasions.

“We do know that COVID-19 positive clusters at the city (government facilities) have, in some cases, originated in gatherings in lunchrooms and other areas, when strict mask (wearing) was not practiced and physical distancing guidelines were not followed,” the email said. He urged employees to practice those guidelines because “now is not the time to let our guard down.”

On Aug. 3, Caldwell issued an executive order banning indoor and outdoor social gatherings on Oahu of more than 10 people due to the surge of COVID-19 cases on Oahu.

Caldwell’s Wednesday email to employees was prompted by a state Department of Health press release earlier in the day that said “an employee potluck at Honolulu Hale is a potential transmission source for 11 cases of illness among City and County of Honolulu workers.”

A flier, obtained by the Honolulu Star-Advertiser, invited city workers to attend a farewell party for a longtime employee in the Purchasing Division that was to take place on the building grounds in late July.

Caldwell, at a hastily called press availability Wednesday, insisted that city officials, after looking into the matter, found no one at that particular party who had tested positive.

Janice Okubo, a Health Department spokeswoman, later clarified that investigators were told by some at the city who tested positive that they had attended a potluck, although it was unclear where or when. It was only noted as a “potential source of transmission” and the investigation is ongoing, she said.

Caldwell said he only learned about the party Wednesday and that he would’ve told organizers not to hold it despite the social distancing guidelines they appeared to have followed.

The event was held on the Diamond Head lawn of Honolulu Hale, not indoors, and the roughly 25-30 people who attended were required to wear masks and practice social distancing, the mayor said. The attendees wished the retiree well and returned to their offices with their bentos, he said.

Caldwell said city employees have been gathering for lunch in lunchrooms and around water coolers since he put out the new executive order last week urging people to distance themselves from people not within their immediate families.

“We learned that city employees have been gathering in lunchrooms and in other places. It could be in a conference room that’s vacant, to talk story or to have lunch and those kinds of things,” Caldwell told reporters Wednesday.

Outside of City Hall, “we do know that there have been other gatherings in other parts of the city whether they be pau hana parties or, in certain cases, parties on the beach before we shut down our beaches that we are now doubling back to say ‘you can’t do this, we do not want you to do this.’”

Council Chairman Ikaika Anderson said he thought it was “a dumb idea” for the retirement party to take place. But he also chastised the Health Department for focusing on the event while refusing an offer that he and Caldwell made to provide a share of the city’s federal CARES Act funding for the training of more contact tracers.

“How about accepting our offer of contact tracing kokua so we can save lives,” Anderson said.

Caldwell shut down Honolulu Hale to the public effective Tuesday after he announced Monday that he learned that morning of a COVID-19 cluster of 11 employees, including one person from his personal administrative staff. Exceptions are being made for those who need to drop bill payments, plans or other documents.

At the same time, he instructed city employees who can telework from outside the office to do so.

City officials said Monday that they knew of 49 positive cases among city employees who work around the island. Of those, they said, nine came from the Department of Budget and Fiscal Services.

City spokesman Alexander Zannes said 474 city employees from Honolulu Hale as well as the nearby Mission Memorial building and the Frank Fasi Municipal Building were tested for coronavirus at a makeshift testing station in the Honolulu Hale courtyard on Monday.

Caldwell was tested and it came back negative, Zannes said.

Caldwell said two city employees who were tested Monday had come back with positive results.