A number of COVID-19 clusters that have popped up this week on different islands reveal many workers in high-risk environments remain unvaccinated and are spreading it to other unvaccinated co-workers and students.

The state Department of Health this week is investigating several COVID-19 clusters associated with a luau production company on Maui, a performing arts center on Oahu, a construction job site at a Molokai hospital and a state public safety training center on Oahu.

Health officials in this week’s cluster report warned that singers and performing artists are in “high-risk environments” when they are indoors with poor air ventilation, lack of physical distancing and inconsistent mask- wearing.

Officials said two dancers from the luau production who tested positive for COVID-19 transmitted the virus to others while doing their makeup unmasked, changing costumes and spending more than 15 minutes in dressing areas.

They recommended that the production increase airflow in its dressing areas and that dancers spend less time unmasked. No additional cases were reported after these changes were implemented and enforced, health officials said in the report, which reflects clusters under investigation in the past 14 days.

DOH also investigated another cluster on Oahu involving a performing arts center that resulted in 25 COVID-19 cases.

In this cluster, three adults infected with COVID-19 interacted with performing arts students, resulting in the infection of three dance students by two adults at two different dance sessions.

The third adult, a voice teacher who taught at the center and at home, ended up infecting seven out of nine students, according to the Health Department.

In all, 19 confirmed cases were associated with the vocal instructor, health officials said, due to inconsistent mask use by the instructor and no mask use by students.

The instructor wore a mask during lessons but took it off to demonstrate proper singing techniques. Students, on the other hand, did not wear a mask when singing.

Students who got infected ended up infecting their household members.

Officials said this cluster is consistent with other cases demonstrating the SARS-CoV-2 virus can be highly transmissible during singing.

All contacts of the vocal instructor who were fully vaccinated, however, tested negative for COVID-19.

Molokai General Hospital officials learned Tuesday that a contractor who tested positive for COVID-19 on Maui had been at the hospital last week.

The hospital’s president, Janice Kalanihuia, said officials immediately shut down the job and tested 12 people who had been on-site. Four tested positive and were quarantined in their housing on Molokai.

She said the contractor and crew were working in the area of the dining room, which had been completely sealed off from the hospital staff and patient care areas.

The air-handling system was disconnected, so no air exchange occurred between the work area and the hospital, she wrote.

Kalanihuia said when hired, the contractor “provided a lengthy and robust COVID-19 protocol they would be following.”

The contractor also signed up for an app used by The Queen’s Health Systems to track employee symptoms daily, but there has to be proper oversight, which the company assured hospital officials it would do.

The contractor declined to make a public statement, and the hospital president did not name the contractor.

Kalanihuia told the Molokai community, “No matter who brought it here, no matter who is infected now, the one thing we need to keep doing is to keep our masks on and socially distance when outside your immediate family or with people whose vaccination status is not certain.”

The Department of Public Safety confirmed Friday that in addition to two confirmed positive cases Wednesday, 12 more employees working at its Training and Staff Development building tested positive.

Public Safety said DOH had been conducting contact tracing, but no details on how the disease was transmitted were available. Also, voluntary testing was available Friday morning for all workers at the building.

Public Safety spokeswoman Toni Schwartz said in a written response to the Honolulu Star-Advertiser that the department is unable to provide a percentage of the number of its employees who are vaccinated since staff are not required to report their private medical information, which includes whether they have been vaccinated.

Public Safety, which oversees all the state’s jails and prisons, said the vaccine was offered to all employees through community distribution clinics and mobile points of distribution.

“Vaccinations are a critical part of the Department of Public Safety’s (PSD) efforts to mitigate spread of the virus among our employees as well as the inmate population,” she said.

Large outbreaks occurred during the pandemic at Oahu Community Correctional Center and the Saguaro Correctional Center in Arizona, where some Hawaii inmates are housed, despite efforts to reduce and prevent overcrowding.

A corrections recruit graduation planned for Friday was postponed.

“We don’t yet know the impact this will have on the recruit class training,” Schwartz said. “PSD is evaluating the situation and awaiting further guidance from DOH to determine next steps.”

On Oahu the Health Department is also investigating a cluster involving restaurants that resulted in 38 coronavirus cases, along with three clusters at “other occupational settings,” a category that includes offices, retail establishments and first responders, resulting in 44 cases.

In Maui County the highest number of cases, 98, has resulted from four clusters in the travel, lodging and tourism category.

Health officials are also investigating two clusters that resulted from a youth football tournament, the Pylon Mecca 7v7, held in late April in Utah and Nevada.

To date, there have been 17 cases on Oahu and 19 cases on Maui tied to the tournament.

On Kauai, officials are investigating two clusters from restaurants that have resulted in 32 cases so far.

In Hawaii County, only one cluster at an education setting is under investigation, with five cases, according to the DOH.

On Friday the DOH reported one new death and 83 new COVID-19 cases.

A Maui woman in her 50s, who had been hospitalized with underlying conditions, contracted COVID-19 and died. By island, there were 64 new cases on Oahu, 12 on Maui, two on Kauai, one on Hawaii island, one on Molokai and three out of state.