Metal Working Fluids

Control Measures

Occupational exposure to metal working fluids (MWF’s) can occur in the metal working industry if controls, including safe working practices and personal protective equipment (PPE), are not used.

Health and safety regulations require exposure to metalworking fluids by inhalation to be prevented where reasonably practicable, or failing that, adequately controlled.

The health hazards can largely be eliminated if good practice is followed. Enclosing the machining process is an effective way of significantly reducing exposure to MWF mist and vapour.

In practice, reducing exposure to an adequate level will involves a mixture of equipment and ways of working. The following general principles should be applied:

• Safe systems of work should be implemented when working with MWFs.
• Where provided, splash guards should be used to control splashing and misting.
• Mist and vapour should be minimised by controlling the volume and rate of delivery of the fluid to the tooling.
• Enclosures or ventilation systems should be used to remove or control any mist or vapour produced.
• A time delay should be introduced before opening doors on machine enclosures to ensure all mist and vapour have been removed by ventilation.
• If possible, natural ventilation should be improved by opening workroom doors and windows.
• Compressed air should not be used to remove excess MWFs from machine parts or equipment.

Under certain circumstances Respiratory Protective Equipment (RPE) may be required e.g. when using a high pressure water hose that creates a mist during sump cleaning.

Respiratory protective equipment (RPE) should only be used as a last resort and only when all other actions have been taken to contain and control exposure.

Where a respirator is needed:

• RPE with a UK Standard Assigned Protection Factor (APF) of at least 20 will normally be required.
• Workers must have had a face-fit test to ensure tight-fitting respirators fit properly and be clean shaven for this type of respirator to work effectively.
• Workers should be trained to use, check and clean the respirator.
• The filters or disposable respirators should be changed regularly.
• The equipment should be stored in a clean, dust-free place such as a container.
• If any defects are found, or the respirator does not fit, is dirty or its filter is old, it should be replaced.
• If there is a risk of a confined space, air-fed RPE must be used.

The following COSHH essentials information sheets for machining with MWFs are designed to help workshop managers introduce effective control measures.

• Advice for managers (MW0)
• CNC machining (MW1) 
• Sump cleaning: water-mix fluids (MW3)
• Managing fluid quality (MW5)

A good practice guide for Safe Handling and Disposal of Metalworking Fluids has also been developed by the United Kingdom Lubricants Association (UKLA) Metalworking Fluid Product Stewardship Group (MWFPSG) with support from the Health and Safety Executive and other industry experts.