Many hardwood dusts are random sensitisers and can cause allergic respiratory, eye and skin reactions both after short term and long term use.  P2 respiratory, eye and disposable glove protection should be primary PPE requirements.  Hypersensitivity pneumonia (alveolitis) has been observed, occurring in much the same way as the lung reaction to Isocyanates in 2-Pack Paints.  The sap and oils of some hardwoods can cause a toxic chemical reaction with a variety of symptoms including headaches, salivation, thirst, giddiness, nausea and irregular heartbeat.  Nasal Cancers are a possibility with a latency period of up to 45 years and occurring to the extent of 7 in 10,000 in those heavily exposed.