Metal Working Fluids

Metalworking fluids (MWFs) - sometimes referred to as suds, coolants, slurry or soap – are water-based fluids used during the machining of metals to provide lubrication and cooling, and to help carry away debris such as swarf and fine metal particles.

Oil mists are generated when high pressure fuel oil, lubricating oil, hydraulic oil, or other oil is sprayed through a narrow crack, or when leaked oil connects with a high temperature surface, vaporises, and meets low air temperature.


Oil mists and MWF exposure is typically associated with machine metal working due to the high level of moving parts and liquid sprays.

If the mist from oil or MWFs are either inhaled, touch unprotected skin, enter wounds or broken skin, or get access to the eyes or mouth - they could affect employee health and lead to a number of varying illnesses.

Exposure to such fluids can cause irritation of the skin, occupational asthma, bronchitis, irritation of the respiratory tract, general breathing difficulties or in extreme cases, can see individuals develop a serious lung disease called extrinsic allergic alveolitis

As an employer, you are responsible for taking effective measures to control exposure and protect health.


Oil mists and MWF aerosols have a legal limit called a ‘workplace exposure limit’ the WEL is set at 5 mg/m3 and 1210 mg/m3 respectively (averaged over an 8-hour working period). In addition the overall WEL there may be specific additives that require monitoring with much lower WEL’s.

Another aspect of exposure that must be considered with MWF’s is the risk from biological contamination such as Legionella.

Once an assessment has been carried out to measure the exposure levels of each target any actions should then be taken to either reduce or control exposure as part of an ongoing monitoring regime.

There are a number of good practices that can be implemented to control exposure and these should be considered.

Click here to learn more about how to reduce exposure to MWF's & Oil Mists


Our consultants are here to help you with advice and guidance. We offer a free consultation service to identify an exposure sampling and monitoring regime that will ensure you meet regulatory compliance and is appropriate for the type of MWF and Oils used in your organisation.

We will then provide you with a no obligation proposal to attend your premises to carryout the site exposure assessment based on the monitoring regime most appropriate for your organisation.


If you need any further assistance with mould in the workplace or would like to know more please get in touch and we will get back to you as soon as we can.

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