The Oak Bluffs Fire Department will be performing a drill at the Martha's Vineyard Hospital Wednesday night. 

At about 6 p.m., passersby may see fire trucks and a ladder truck extending to the roof of the hospital. 

"We want to assure the public that this is only a drill," the hospital wrote in a statement. 

The fire department expects the drill will last about two hours and could impede traffic on the Lagoon Pond side of the building.