Occupational Hygiene News
Working Safely with Metalworking Fluid
Metalworking fluids (MWFs) are used to reduce heat and friction and to remove metal particles in industrial machining and grinding operations. There are numerous formulations, ranging from straight oils (such as petroleum oils) to water-based fluids, which include soluble oils and semisynthetic/synthetic fluids. MWFs may be complex mixtures of oils, emulsifiers, anti-weld agents, corrosion inhibitors, extreme pressure additives, buffers (alkaline reserve), biocides, and other additives.
In use, the fluid complexity is compounded by contamination with substances from the manufacturing process (such as tramp oils, hydraulic fluids, and particulate matter from grinding and machining operations). Furthermore, water-based metalworking fluids support microbial growth, which introduces biological contaminants (such as bacterial and fungal cells or cell components and their related biological by-products such as endotoxins, exotoxins, and mycotoxins).
Workers can be exposed to the fluids by breathing aerosols generated in the machining process, or through skin contact when they handle parts, tools, and equipment covered with the fluids.
Occupational exposures to metalworking fluids may cause a variety of health effects. Respiratory conditions include hypersensitivity pneumonitis (HP), chronic bronchitis, impaired lung function, and asthma. Work-related asthma (WRA) is one of today’s most prevalent occupational disorders, imposing significant costs in healthcare and workers’ compensation.
Dermatologic exposures are most commonly associated with, but not limited to, allergic and irritant dermatitis (skin rash). In addition, substantial evidence shows that past exposures to some metalworking fluids were associated with increased risk of some types of cancer. Although actions taken in the last several decades have reduced that risk, it is not known if these actions have totally eliminated the risk.
A panel of experts from the UK Lubricants Association (UKLA Metalworking Fluid Product Stewardship Group FPSG) and from the Health and Safety Executive (HSE) have published a Good Practice Guide for Safe Handling and Disposal of Metalworking Fluids (version 2) which provides a guide on how to maintain MWF to prevent ill-health in machine workshops.