Why not just install, in each casket, a pop-off valve that slowly releases gases from the casket. It appears that what goes on in the casket is inevitable unless there is a procedures that folks with money can afford; but for the day-to-day folks this might work. It won’t activate for maybe months or years down the road but it might prevent casket explosion. Gaskets don’t last anyway, if its a grave grass and water will get in anyway and there goes your warranty – which you won’t know happened anyway. What do you think?