Nuclease required for the repair of DNA interstrand cross-links (ICLs) (PubMed:25779053). Acts as a 5'-3' exonuclease that anchors at a cut end of DNA and cleaves DNA successively at every third nucleotide, allowing to excise an ICL from one strand through flanking incisions (By similarity). May act upstream of the helicase RECQL4A and the ATPase RAD5A, which is involved in error-free post-replicative repair. Functions independently of MUS81 pathway, but in a similar pathway with RECQ4A, RAD5A and MFH1 in ICL repair (PubMed:25779053). Hydrolytically removes 5'-nucleotides successively from the 3'-hydroxy termini of 3'-hydroxy-terminated oligonucleotides. Binds 2 magnesium or manganese ions per subunit. Localizes to stalled replication forks via its UBZ-type zinc finger. Belongs to the FAN1 family.