Removes the secondary (acyloxyacyl-linked) fatty acyl chains from the lipid A region of bacterial lipopolysaccharides (PubMed:1883828, PubMed:29343645, PubMed:8089145). By breaking down LPS, terminates the host response to bacterial infection and prevents prolonged and damaging inflammatory responses (By similarity). In peritoneal macrophages, seems to be important for recovery from a state of immune tolerance following infection by Gram-negative bacteria (By similarity). {ECO:0000250|UniProtKB:O35298, ECO:0000269|PubMed:1883828, ECO:0000269|PubMed:29343645, ECO:0000269|PubMed:8089145}. This is the function of AOAH (acyloxyacyl hydrolase, Ensembl gene identifier ENSG00000136250).