A block fitting for a fluid system comprising: a male block including a bore extending therethrough adapted for connection to the fluid system; a female block including a bore extending therethrough adapted for connection to the fluid system; the male block having a radial annular surface surrounding the bore , an annular lip defining an inner cylindrical surface surrounding the radial annular surface and extending toward the female block , and a planar longitudinal inner end surface facing the female block ; the female block having a radial annular surface surrounding the bore , an annular groove surrounding the radial annular surface sized and positioned to receive the annular lip of the male block , and a planar longitudinal inner end surface facing the male block ; the male block and female block joined together with the bores aligned and the radial annular surface of the male block and the radial annular surface of the female block spaced apart in facing relation; a primary seal member having an annular body portion disposed between the radial annular surfaces of the blocks surrounded by the inner cylindrical surface of the lip ; and a secondary seal member spaced apart from the primary seal member and positioned between the planar longitudinal inner end surfaces of the male block and female block for axial compression when the male block and female block are secured together, characterized in that the male block defines a shoulder projecting longitudinally from the planar longitudinal inner end surface , the shoulder defining an outer cylindrical surface , and wherein the secondary seal member is located at a junction of the outer cylindrical surface and the planar longitudinal inner end surface of the male block . a male block including a bore extending therethrough adapted for connection to the fluid system; a female block including a bore extending therethrough adapted for connection to the fluid system; the male block having a radial annular surface surrounding the bore , an annular lip defining an inner cylindrical surface surrounding the radial annular surface and extending toward the female block , and a planar longitudinal inner end surface facing the female block ; the female block having a radial annular surface surrounding the bore , an annular groove surrounding the radial annular surface sized and positioned to receive the annular lip of the male block , and a planar longitudinal inner end surface facing the male block ; the male block and female block joined together with the bores aligned and the radial annular surface of the male block and the radial annular surface of the female block spaced apart in facing relation; a primary seal member having an annular body portion disposed between the radial annular surfaces of the blocks surrounded by the inner cylindrical surface of the lip ; and a secondary seal member spaced apart from the primary seal member and positioned between the planar longitudinal inner end surfaces of the male block and female block for axial compression when the male block and female block are secured together, characterized in that the male block defines a shoulder projecting longitudinally from the planar longitudinal inner end surface , the shoulder defining an outer cylindrical surface , and wherein the secondary seal member is located at a junction of the outer cylindrical surface and the planar longitudinal inner end surface of the male block . <EOS>