Has anyone come across the need to dip test the cutting oil used on lathes, band saws and milling machines, for bacterial growth? If so, is it difficult?

Clark It is essential that your company manages the risks from MWFs. Your oil supplier will give you expert advice on this for nothing, and would conduct the dip slide tests for your company, for a fee. They will also "for a fee" produce the records that you need and do any necessary training on MWFs for employees that are at risk. I would discuss this with the engineer responsible and ask him /her to involve the oil supplier regards Steve

Before I joined my current employer the engineering section received a letter from HMI regarding this issue as there are several lathes and presses with "White Water" recirculation & filtration tanks. The reference quoted from the HSE pointed towards their COSHH series - MW5 http://www.hse.gov.uk/pubns/guidance/mw05.pdf Small 2 chamber incubators (search for "Gnat Incubator") can be redaily purchased on-line along with the dip slides - 5 minutes test, wait for the incubation period then record the results. Cost < £100 p.a. We now have the production Manager dip testing as part of his weekly start up routine and after 18 months have not seen significant microbial activity warranting either addition of biocide to the white water or a full drain and clean down of the system.

Thanks for all your help. The fluid supplier would give no advice whatsoever, suggesting this would come from the HSE. All the HSE has said is "do it". Does anyone know where specialist advice is available?

Clark I would suggest that you consider changing your oil supplier, oil suppliers are very competitive and should be keen to help. Take a look at this site http://www.ukla.org.uk/MWFPS1.htm If you pm me I will send you a MWFs Management Program that I recently wrote for a client and this starts by callingin the oil supplier, it should give you some practical ideas in addressing your problem regards Steve

Managing water mixed metalworking fluids in a workshop environment is not as simple as many might assume. Ian has rightly pointed out some of the complexities with regard to bacterial contamination. However, there are other health considerations. Water mixed metalworking fluids will contain a variety of constituents, many of which have implications for worker exposure. For example, the emulsifier will be a relatively potent skin and respiratory irritant. Some of the constituents will almost certainly be skin (and probably respiratory) sensitisers. The higher the concentration of these in the mixture as used in the machine tool the greater the potential for health effects, so managing mixture strength is essential. Another common problem is that of tramp oil. It is not unusual when carrying out a dermal exposure audit to find that the fluid tank is showing a high level of tramp oil. This encourages the growth of micro-organisms and can, itself, represent a skin hazard. It is most obvious when a machine is switched off, as the oil then rises to the surface. Tramp oil can be easily dealt with by using a suitable device, such as a skimmer. Fluid temperature is another consideration, particularly, for example, where a machine is removing large amounts of metal. Elevated temperature encourages bacterial growth and reduces the life of the fluid. Yet this does not appear to have been considered in many machines. Simple fluid cooling systems are available. Filtration systems on grinding machines are another problem I often encounter. The fines will pass through many of the ‘standard’ filters on these machines. They then cause physical damage to the operator’s skin increasing the potential for both dermatitis and infection. Of course, what is important is the level of exposure of the operator (and others). I sometimes wonder when looking at the design, even of modern machine tools, whether operator exposure to the fluid has even featured in the designer’s thinking. Depending upon the machine design there are various ways of eliminating or significantly reducing operator exposure, thus reducing exposure to both chemical and biological hazards. Given that a hazard only presents a risk when there is exposure, surely this should be the priority. Chris