Metalworking fluids (MWFs) can cause occupational asthma if you inhale the mist or vapour generated during machining/shaping operations. MWFs can also cause dermatitis.
Follow the link to the metalworking fluids MWFs site for more information
There have been several outbreaks of asthma-like disease using MWFs.
See COSHH Essentials for detailed advice on control.
Minimise mist by enclosing the machine head as much as possible. Provide low misting fluids delivered to the cutting tool at the right rate. Provide mist extraction on enclosed machines.
You can find more guidance and information for engineers on the Asthma publications pages.