Blowout preventer (BOP) stack and lower marine riser package for sealing an undersea well. The blowout preventer stack includes a frame extending along an axis and configured to be attached to a head of the well; an accumulator attached to the frame and configured to provide high pressure; two or more BOPs attached to the frame, the two or more BOPs being disposed within the frame and attached one on top of the other along the axis; each BOP having a body and a pair of bonnets attached to the body, where the bonnets are configured to be detachably attached to the body; each BOP having a corresponding cavity extending along the axis through which a fluid from the well is circulating; each BOP being configured to seal the well when the high pressure from the accumulator is released to the BOPs; plural brackets attached to the body of at least one BOP; and a safety bar attached to the plural brackets and configured to partially encircle the body of the at least one BOP.