Working safely with MWF’s – Do & Don’ts

Guidance on the safe use of MWF

Exposure to Metalworking Fluids (MWFs) can cause health problems in some circumstances. These guidelines will help minimise such risks, maintain MWF quality and help prolong machine and tool life.




Assess risks, refer to the Safety Data Sheet and manage MWFs properly

Regularly check for dermatitis and respiratory problems and report symptoms promptly.

Wait for outbreaks of dermatitis or respiratory problems.


Store packages and drums correctly.

Expose to excessive heat or cold or allow rain water to accumulate on the top.

Maintenance of fluids and coolant systems

Make trained personnel responsible for MWF maintenance.

Ensure regular monitoring of the MWFs including testing for bacteria and pH.

* Add biocide indiscriminately.

Record and act on the MWF condition monitoring results.

Use any MWF beyond its useful working life.

Mix MWFs and top-up sumps correctly.

* Add biocide indiscriminately.

  • Keep the machine clean.
  • Keep the MWF tank covered.

Allow the MWF to be contaminated with rubbish or
food waste.

Use filters to remove swarf and fines.

*Allow tramp oil to accumulate.

Are you working safely with metalworking fluids?

Cleaning and filling coolant systems

Thoroughly clean sump, pipework, machine and guards
before re-filling with fresh MWF.

Put clean MWFs in dirty machines or sumps.

Use a system cleaner compatible with the MWF.

Dispose of used MWFs directly into public drains or sewers.

*Use a mixing valve or a clean container to prepare water-mix MWFs.

*Mix MWFs in the machine sump tank.

*Use drinking-quality water of the correct hardness.

*Use water from fire hoses or contaminated sources.

*Use a refractometer to check the MWF is at the correct dilution.

*Check MWF concentration by feel.

Use protective equipment (PPE) when handling MWFs and when cleaning out machines.

Avoid using compressed air, use alternatives to clean components where reasonably practicable. Carefully consider the risks, if you must use compressed air, use a low pressure and adopt suitable controls to protect health.

Use high pressure air lines to blow components clean.

Operation of machines

Provide training and instructions for employees in the safe use of MWFs and correct use of PPE.

Allow the MWF to overheat.

  • Enclose the process where possible.
  • Ensure correct MWF flow and delivery.

*Allow stagnation of water-mix MWFs.

  • Provide local exhaust ventilation (LEV) where necessary.
  • Use all machine guards and spray covers properly.

Allow mist or spray to be emitted into the machine shop.

Follow correct working procedures.

Require operators to put their hands into MWFs unnecessarily.

Observe good personal hygiene.

Eat, drink or smoke near machines.

*Guidelines in blue text refer to actions when using water-mix MWFs.

Black text refers to both water-mix and neat MWFs.

Not all the points are specific legal requirements, but all can help employers comply with the COSHH Regulations. If in doubt, contact your MWF supplier.

Matthew Bloomer

From our expert Matthew Bloomer

Matthew has been working for Q8Oils since 2008 and is an expert in Metalworking fluids, more specifically in biocides and microbiology - which can be explained by his background in chemistry.

Ask Matthew Bloomer

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