A man wearing a protective mask is seen on a subway platform on March 9, 2020 in New York City.

Massachusetts' Governor Charlie Baker declared an emergency after the state's coronavirus cases more than doubled overnight, surging by 51 new cases.

"Today there are 51 new presumptive positive cases of COVID-19, bringing the total number of confirmed or presumptive positive cases in the commonwealth to 92," said Marylou Sudders, secretary of Massachusetts' health and human services.

Sudders said 70 of the total cases all stem from a meeting of senior managers at Biogen Inc. in the Boston area late last month. Presumptive positive cases have been confirmed by state or local labs, but not by the Centers for Disease Control and Prevention.

The declaration of an emergency gives the state more flexibility to respond to the evolving outbreak, Baker said.