A cytochrome P450 monooxygenase involved in the metabolism of the pro-inflammatory lipid mediator leukotriene B4 (LTB4). Hydroxylates at the omega-1 and omega-2 positions LTB4. This oxidation step leads to LTB4 inactivation, which is postulated to be a crucial part of the resolution of inflammation. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (CPR; NADPH-ferrihemoprotein reductase). leukotriene B4 + O2 + reduced [NADPH--hemoprotein reductase] = 18-hydroxy-leukotriene B4 + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] leukotriene B4 + O2 + reduced [NADPH--hemoprotein reductase] = 19-hydroxy-leukotriene B4 + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Lipid metabolism; leukotriene B4 degradation. Belongs to the cytochrome P450 family.