Abstract: An overpressure relief plug for safeguarding pressure gauges that tend to damage due to internal overpressure comprising a safety plug for interference sealing fit application to an aperture formed in the pressure gauge housing that otherwise communicates the housing chamber that may be subject to overpressure to the ambient atmosphere, which plug is formed from silicon elastomer to define a shank that is pressed into the housing aperture, a grip portion on one end of the plug shank that is to aid in initially applying the plug to the housing as part of the gauge assembly procedure, and a stop cap at the other end of the shank that forms a head for the plug and that is spherically contoured and defines a planar stop annular surface thereabout having a marginal rim proportioned for firm sealing engagement with the exterior surface of the housing on application of the plug to the housing, with the plug shank and aperture being proportioned to "pop out" of the housing aperture when the pressure of the housing ch