<p>The ball valve coupling includes first and second ball valve units having interengageable lugs for releasably connecting the ball valve units in face-to-face relation. The first ball valve unit includes a ball valve movable between open and closed positions. A safety lock-out key is mounted on the first ball valve unit for movement from a first position toward a second position in response to partial engagement of the lugs on the first and second ball valve units. A stem pin is mounted on the first ball valve unit for movement with the ball valve between the open and closed positions. The safety lock-out key is moved from the first position and when the ball valve is in the closed position to prevent movement of the ball valve to the open position. The stem pin engages the lock-out key when the lock-out key is in the first position and when the ball valve is in the open position to prevent movement of the lock-out key from the first position.</p>
