Photocopiers and laser printers use toner as part of the printing process. The toner is an extremely fine powder, which in itself is not classed as a substance hazardous to health, but any dust in substantial concentration is, as it may cause respiratory tract irritation resulting in coughing and sneezing.

Toner dust may become airborne for a variety of reasons; toner dust spilled inside the machine becomes airborne by passing through the ventilation fans into the room, the waste toner compartment fills up and causes toner to back up inside the machine, or the most common, careless renewal of the toner cartridge causes a spill of toner into the room.

Toner dust is considered a nuisance dust and should have no health effects other than those noted above. However, persons who have an already compromised respiratory system (e.g. suffer from asthma, bronchitis, etc) should avoid changing toner cartridges. If this is not practicable then the operation should be carried out with extreme caution to avoid generating a dust cloud.

Should any toner be spilt, it is best to vacuum up, rather than brush off, as much as possible to avoid raising a dust cloud. The remainder should be removed using a damp cloth rinsed in cold water. Hot water should be avoided as it may cause the toner to partially melt and become sticky. Toner may be disposed of as normal waste, though it should be placed in a sealed bag to contain the fine powder.