Cutting fluids used in metalworking and machining processes include oils, pastes, gels, oil-water emulsions, mists and gases. Cutting fluids are made from petroleum distillates, animal or plant oils, water and air. Metal cutting operations generate heat, so the cutting fluids used are coolants which speed up the work and reduce friction. Cutting fluids also need to contain a lubricant to prevent friction between the cutting edge and the chip. Cutting fluids can be worked with in various ways including brushing, dripping, misting, spraying and flooding. This can be carried out through high pressure and high volume. However, working with these cutting fluids can pose risks to workers’ health. Mist, for example, can settle on the skin or be breathed in. One may be splashed or splattered by the fluid or there may be injury by handling the tooling parts of the cutting process.
One of the main risks from metal working fluids includes dermatitis. According to the HSE, there are about 200 cases of dermatitis reported every year as a result of handling coolants and lubricant cutting fluids. This can include irritant and contact dermatitis as well as occupational acne. Dermatitis can be caused by sensitising agents such as chromium, nickel and cobalt and also from chemicals used to kill biocides which are added to cutting lubricants. Another growing concern is asthma, bronchitis and irritation of the respiratory tract. Exposure to these fluids can also cause irritation to the eyes, nose and throat. These conditions can result due to mist coming from cutting fluids. There has been an increased risk of several kinds of cancer due to this kind of work. The carcinogenic substances produced from cutting fluids may include polycylic aromatic amines and nitrosamines. The substitution of cancer-causing chemicals in metalworking fluids greatly reduces the risk of cancer.
However, if suitable precautions are taken and the metalworking fluids properly managed, this risk is minimal. Safe practices when working with metal working fluids include good ventilation, splash guards and personal protective equipment (PPE). PPE can include respiratory apparatus, gloves and goggles. Bacterial growth is mainly found in oil based cutting fluids, so lowering the fluid temperature and timely fluid replacement may discourage bacterial growth. The production of vapour and mist can be minimized by controlling the volume and rate of delivery of the fluid. The hands should be protected by always wearing gloves and avoiding direct contact with wet work surface areas. Pre-work and after work creams, although not a protective barrier, can help restore the natural moisture to the skin. Hands should be washed thoroughly before eating and drinking. If exposure to metalworking fluids cannot be prevented, the employer must supply regular health checks. Skin should be checked for lasting changes such as cracking patches and dryness. One’s breathing and any chest complaints should also be monitored, changes recorded and all possible control measures taken to keep the health of the individual. Water-mix wash fluids used to clean components may also pose a hazard and can cause complications. The same precautions should be taken when exposed to them as that used for cutting fluids.
The video below, although made in a a Machine Shop in 1950, is still relevent today in Industrial Dermatitis Prevention