More than six years have passed since the outbreak of serious respiratory disease at Powertrain and we still don’t know the cause.
Admittedly, it appears to be linked to the use of metalworking fluids but what the exact causative agent is in these fluids is unknown. Extrinsic Allergic Alveolitis can have a permanently debilitating and disabling effect, and like asthma can, in rare circumstances, also be fatal.
Metalworking fluids (also known as suds, coolants, slurry or soap) have been said to be the ‘lifeblood’ of engineering. So, for manufacturers who depend on their use, what are they supposed to do? How can manufacturers best reduce the risk to their employees when they don’t know what to control?
Fortunately, EEF has teamed up with HSE to put a mark in the sand and produce some clear guidance. EEF has agreed a six-step approach to the management of water-based metalworking fluids which means users need to:
Essentially, as well as maintaining the quality of the fluid and minimising bacterial contamination, proper control boils down to having effective systems in place to control the mist arising from use of the fluids.
The amount of mist generated by machining depends on a number of factors including the speed of rotation of the machine tool, the pressure of application of the fluid and the geometry of the work-piece. As a result, some processes tend to create more mist than others and some produce high levels of very fine mist that can be inhaled deep into the lungs; for example grinding, whilst others, such as reciprocating sawing produce little or no mist.
Most modern CNC lathes are generally high speed and capable of creating coolant mist. So, the starting point for risk assessment of high speed machining will generally be to provide full enclosure as well as efficient local exhaust ventilation, vented to the outside.
In any event, your risk assessment needs to consider the particular conditions, working practices and experience at your workplace. However, it’s worth remembering that while proper control will reduce the incidence of respiratory ill-health, it may not prevent all cases.
HSE continue to undertake research in this area. Where cases of respiratory ill health arise despite all of the accepted control measures being in place, HSE enforcement action is unlikely to be justified given the current state of knowledge.