Filter with retained safety element

A filter comprising a housing extending along an axis between first and second axial ends, a closed loop primary filter element extending axially in said housing between first and second axial ends respectively adjacent first and second axial ends of said housing, said primary filter element having a hollow interior, a closed loop safety filter element in said hollow interior of said primary filter element, said safety filter element having an end cap at said first end of said housing, said primary filter element having an end cap at said first end of said housing, a sealing flange extending from said first end of said housing axially toward said second end of said housing and being radially between said end cap of said safety filter element and said end cap of said primary filter element, said flange circumscribing said hollow interior, said flange having an inner sealing surface facing radially inwardly towards said hollow interior and engaging said end cap of said safety filter element in radially compressive sealing relation, said flange having an outer sealing surface facing radially outwardly away from said hollow interior and engaging said end cap of said primary filter element in radially compressive sealing relation, said safety filter element extending axially between first and second axial ends respectively proximate said first and second axial ends of said primary filter element, wherein said safety filter element is tapered to a narrower lateral width at said second end relative to said first end to provide lateral clearance between said second end of said safety filter element and said second end of said primary filter element in said hollow interior of said primary filter element to permit lateral rocking back and forth of said second end of said primary filter element during removal thereof, without dislodging said safety filter element, and wherein said flange has a detent engaging and retaining said end cap of said safety filter element in interference fit independently of said primary filter element to retain said safety filter element in said housing upon removal of said primary filter element from said housing.