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Metal Working Fluids (MWF) – Are you managing them properly?

Exposure to metalworking fluids can cause both irritation of the skin/dermatitis and lung diseases, such as occupational asthma and occupational hypersensitivity pneumonitis.

HSE has throughout this year been making an effort to raise the awareness of the issues relating to the use of and exposure to metal working fluids, especially where CNC machines are concerned, where LEV need to be utilised. If this is an area of safety you manage but you have not been visited by HSE this year, then look at what you are doing and ensure you will not be failing foul of any legal requirements covering this issue.

Fluid systems that contain water or water-mixes can become highly contaminated with harmful bacteria and this bacterial contamination of fluids and associated machinery and pipework should be monitored and controlled.

The Control of Substances Hazardous to Health Regulations (COSHH) require exposure to metalworking fluids by inhalation, ingestion or through direct contact with the skin to be prevented where reasonably practicable, or if this cannot be achieved, to adequately control them. As duty-holder’s employers should:

  • Conduct suitable and sufficient risk assessments (both COSHH and machine use);
  • Maintain fluid quality and control the bacterial contamination of the fluids;
  • Minimise skin exposure to fluids;
  • Prevent or control the airborne risks:
    • apply MWF at the lowest possible pressure and flow volume consistent with adequate lubrication, cooling and swarf removal.
    • apply MWF at the point where the tool and workpiece make contact to minimise mist generation from contact with other rotating parts.
    • stop MWF delivery when not machining, although you will still need to maintain fluid circulation to prevent stagnation.
  • Where there is exposure to MWF, conduct health surveillance.

To achieve control and reduce the risk you should:

  • Check and maintain all enclosures and be aware of any time delay needed between stopping the machine and opening the enclosure to prevent MWF/mists from contaminating the air;
  • Ensure that all local exhaust ventilation (LEV) equipment fitted to CNC machines are being checked regularly by users to ensure housings and ducting is in good repair and that the volume flow rate is correct by checking the air flow meter (if fitted);
  • Ensure that the required Thorough Examination is occurring at no longer than fourteen-month intervals. It does not matter if the LEV is integral with the machine or an added standalone unit, this equipment must be inspected by a competent person to a time scale;
  • Check the levels of bacterial contamination using dip slides or other means of measuring the bacterial activity in both the metalworking and associated fluids, such as in the washing machines, and then act on the readings as per the dictates of your risk assessment;
  • Delegate a responsible person to carry out health surveillance;
  • Conduct Asthma checks;
  • Refer anyone affected by exposure to an occupational health professional;
  • Act swiftly where any diagnosis of ill health occurs so that the actual cause is determined and to allow further exposure to be managed effectively and adequately.

If this alert has raised questions or you need to discuss any other health & safety related issue do not hesitate to contact your health & safety consultant or the main office for advice/assistance. 


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