In one embodiment, the present disclosure provides fail-safe mechanisms for final filters. The fail-safe mechanisms of the present disclosure include a prefilter that is essentially transparent or translucent to TOC contaminants and a microporous filter downstream from the prefilter that filters contaminants by means of size-exclusion, mechanical interception, coagulation, or a combination thereof, the filter being adapted to significantly reduce fluid flow and undergo blockage under a challenge by TOC contaminants. In another embodiment, the present disclosure provides a method of filtration that includes the steps of providing a microporous filter disposed upstream from a final filter, the microporous filter capable of filtering contaminants from a fluid by means of size-exclusion, mechanical interception, coagulation, or a combination thereof, and said filter being adapted to significantly reduce fluid flow and undergo blockage under a challenge by TOC contaminants, and filtering the fluid through the microporous filter