Durham School Services drivers and monitors in Beaufort voted to authorize a strike.
Drivers and monitors voted 93-2 and join those in Charleston and Summerville's Dorchester School District 2 who also authorized a strike, according to a news release from Teamsters Local 509.
Negotiations between Teamsters Local 509 and Durham are scheduled to continue on Tuesday.
"We had to take a strike vote to get Durham to get serious in negotiations. We've met over 39 times with the contractor and they hadn't moved on the key issues of concern to the drivers and monitors," said L.D. Fletcher, president of Local 509, in a statement.
There are about 620 Teamsters Local 509 members at Durham in Charleston, Summerville and Beaufort. Durham is a subsidiary of National Express Group.
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