 Care should be taken to avoid confusing NP-40 with Nonidet P-40 (octyl phenoxypolyethoxylethanol) which is currently out of production.Nonidet P-40 ("Non-Ionic Detergent") was originally manufactured and trademarked by the Shell Chemical Company, but was phased out of production in the early 2000s.Confusingly, biochemical protocols published between the 1960s and 2000s refer to Shell's Nonidet P-40 as NP-40.