NANTUCKET, MASS. (WHDH) - The Nantucket Board of Health on Thursday voted to implement an indoor mask mandate in an effort to combat a recent COVID-19 outbreak on the island.

“There has recently been a significant increase in COVID-19 cases and hospitalizations due primarily to the Delta variant,” the board wrote in an emergency order, which takes effective immediately. “Emerging evidence indicates that the Delta variant is more transmissible than prior variants of the virus, may cause more severe illness, and that even fully vaccinated individuals can spread the virus to others.”

Until further notice, customers and staff at an array of businesses on the island must now wear a mask or face covering while indoors.

Customers at restaurants, bars, and dance clubs can only remove their masks when seated.

The mandate does not apply to informal gatherings at private residences.

Children under the age of 2 and performers who are at least six feet away from customers are also exempt from the mandate.

Those found in violation of the mandate will first receive a written warning. Fines of $100, $200, and $300 will be issued for subsequent violations.

Nantucket County is one of four Bay State counties that is now considered high risk for COVID-19 transmission, according to the Centers for Disease Control and Prevention.

There were 23 new COVID-19 cases reported on the island on Wednesday.

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