Abstract: A portable bulk storage container having a counterweight mechanism for opening and closing a heavy lid. The container comprises a substantially gas and liquid tight tank secured inside of a frame. An opening is positioned on a front portion of a top of the tank. A lid is pivotally connected to the top of the tank for sealing the opening. A pair of fulcrums or connecting members extend from opposite sides of a rear portion of the lid. A counterweight is attached to each fulcrum. Each counterweight has an elongated lever end which extends away from the rear of the lid such that the counterweight can be used to rotate the lid between closed and open positions. Each counterweight is positioned beyond a side wall of the tank such that the counterweights can be rotated along the side wall of the tank, thereby effectively utilizing the limited amount of space available inside of the frame.