But then the Massachusetts state website says, 

Q. Will premium payments be treated as taxable income?

Under current law, premium payments are not subject to state income tax but may be subject to federal income tax. Because the IRS reporting threshold for taxable grants is $600, no 1099-G will be issued from the Department of Revenue. 

https://www.mass.gov/info-details/covid-19-essential-employee-premium-pay-program#additional-informa...