N-nitrosodiethanolamine in commercial cutting fluids without nitrites

We have determined the concentration of N-nitrosodiethanolamine (NDELA) in 11 commercial 'nitrite-free' cutting fluids in Sweden in 1989. The concentrations in diluted fluids after use were 0.02-0.51 ppm. The concentrates contained 0.02-17 ppm. There was no correlation between the occurrence of formaldehyde-releasers, boramines or bacteria and the concentrations of NDELA. An additive in one fluid contained 140 ppm NDELA. The concentration of nitrite in the diluted fluids after use varied between 0 and 40 ppm. There was a correlation between the concentration of nitrite and NDELA. It is concluded that the concentration of NDELA can be low if the suppliers check their additives with regard to NDELA and the users check the concentration of nitrite.