Triazine and other formaldehyde-releasing biocides have been banned from the formulas of metalworking fluids at DaimlerChrysler because of a possible link between the popular biocides and hypersensitivity pneumonitis, an acute and chronic lung disease. Of the most common biocides in use today, only phenolic products routinely controlled and killed a microorganism thats linked to the rare but serious disease, according to Biosan Laboratories.
Two of DaimlerChryslers North American plants have had outbreaks of hypersensitivity pneumonitis, one in the mid-1990s and the other recently, the companys William Watt told the ACGIH Health Effects of Mineral Oil Mist & Metalworking Fluids symposium in Cincinnati last week. The causes of the disease are unknown, but Watts research at DaimlerChrysler, as well as studies at other manufacturing plants with HP outbreaks, including Ford, General Motors, Caterpillar and TRW, point to a relationship between the presence of triazine biocides in metalworking fluids and mycobacteria. Mycobacteria have been linked to HP in many but not all studies.
HP is a fairly common occupational disease; its also called farmers lung, mushroom-workers lung and bird-breeders or bird-fanciers lung. But it is rare in the metalworking environment. There have been only an estimated 200 metalworking-fluid-related cases in the last decade, said Watt. But its important if youre in the plant with the occurrence.
Our immediate plan was to dump all systems with high mycobacteria counts, clean the systems thoroughly, recharge them with non-triazine metalworking fluids, maintain those systems, and conduct periodic testing, Watt said.
Watt found that the use of triazine-based biocides in the metalworking fluid actually increased the mycobacteria count above the levels found in similar fluids containing no biocides. To minimize and control triazine use, Watt, based in Auburn Hills, Mich., said that DaimlerChrysler will use isothiazolone [such as some Rohm and Haas Kathon products], PCMC [such as Bayers Preventol-CMK products] or other broad-based biocides in the fluid formulation or tank side.
Triazine will still be used, but only tank side, and only sparingly, said Watt.
Harold Rossmoore of Biosan Laboratories in Warren, Mich., told the symposium that he found mycobacteria in all eight of the metalworking sites with HP that his company studied. In addition, he found mycobacteria in both soluble and semi-synthetic metalworking fluid formulations where no HP was diagnosed. With several colleagues, Rossmoore has isolated a new species of the organism which he believes can trigger HP.
Biosan tested ten commercial biocide formulations, including triazine [like some of Buckman Laboratories Busan, Archs Triadine and Troys Grotan products], isothiazolone and others. Rossmoore concluded that formaldehyde-condensate products like triazine, even at high doses, do not kill mycobacteria. When its compatible with the fluid, isothiazolone seems to be effective, he said. But only PCMC [phenolic biocides like some of Bayers Preventol products] routinely controlled and killed mycobacteria.
Its not just a triazine issue, contends Richard Rotherham of Troy Corp., in Concord, Ont., whose metalworking fluid additive lines include popular triazine biocides. The question is how you use biocides: whether formulating the biocide in the concentrate is the right way to go for biocides in large systems. Sump-side management is the key to control levels [of microorganisms]. You dont have proper control of biocides in concentrates.
The key is proper fluid management, so you never get the high levels of biomass. Mycobacteria are surely a factor in some way, and the key to control is never letting the counts get too high. From our point of view, thats not a negative.