A shearing device that torsionally shears an oilfield tubular by gripping the tubular at vertically spaced apart locations and exerting a torsional force at the locations. Tong assemblies are provided for gripping the tubular, where the tong assemblies include a tong member pivotally mounted on a tong arm. The tong assemblies may be housed in a blowout preventer mounted on a wellhead assembly; projecting the tong assemblies radially inward engages the tong members with the tubular, and moving the arm further radially inward imparts the torsional force onto the tubular. In an alternate embodiment, the shearing device includes holding rams that project radially inward to engage the tubular and a torque rack that tangentially engages the tubular thereby torqueing the tubular.