Editing Laser printing (section)

==Safety hazards, health risks, and precautions==

===Toner clean-up===
[[Toner (printing)|Toner]] particles are formulated to have electrostatic properties and can develop static electric charges when they rub against other particles, objects, or the interiors of transport systems and vacuum hoses. Static discharge from charged toner particles can ignite combustible particles in a vacuum cleaner bag or cause a small [[dust explosion]] if sufficient toner is airborne. Toner particles are so fine that they are poorly filtered by conventional household vacuum cleaner filter bags and blow through the motor or back into the room.

If toner spills into the laser printer, a special type of vacuum cleaner with an electrically conductive hose and a high-efficiency ([[HEPA]]) filter may be needed for effective cleaning. These specialized tools are called "ESD-safe" (Electrostatic Discharge-safe) or "toner vacuums".

===Ozone hazards===
As a normal part of the printing process, the high voltages inside the printer can produce a [[corona discharge]] that generates a small amount of ionized oxygen and nitrogen, which react to form [[ozone]] and [[nitrogen oxides]]. In larger commercial printers and copiers, an [[activated carbon]] filter in the air exhaust stream breaks down{{citation needed|date=September 2011}} these noxious gases to prevent pollution of the office environment.

However, some ozone escapes the filtering process in commercial printers, and ozone filters are not used at all in most smaller home printers. When a laser printer or copier is operated for a long period of time in a small, poorly ventilated space, these gases can build up to levels at which the odor of ozone or irritation may be noticed. A potential health hazard is theoretically possible in extreme cases.<ref>{{cite web |title=Photocopiers and Laser Printers Health Hazards |url=http://www.docs.csg.ed.ac.uk/Safety/general/photocopiers.pdf |date=2010-04-19 |website=www.docs.csg.ed.ac.uk |access-date=2013-10-22 |archive-date=2013-07-11 |archive-url=https://web.archive.org/web/20130711191442/http://www.docs.csg.ed.ac.uk/Safety/general/photocopiers.pdf }}</ref>

===Respiratory health risks===
{{see also|Toner (printing)#Health risks}}
[[File:NIOSH Scientists Investigating Pollution From Office Equipment.webm|thumb|A video on research done on printer emissions]]
According to a 2012 study conducted in Queensland, Australia, some printers emit sub-[[micrometre|micrometer]] particles which some suspect may be associated with respiratory diseases.<ref>{{cite journal |title= Particle emission characteristics of office printers|vauthors=He C, Morawska L, Taplin L |year=2012 |pmid=17937279 |volume=41 |journal=Environ Sci Technol |issue=17 |pages=6039–45|doi=10.1021/es063049z |url=https://eprints.qut.edu.au/8824/3/8824.pdf }}</ref> Of 63 printers evaluated in the [[Queensland University of Technology]] study, 17 of the strongest emitters were made by HP and one by [[Toshiba]]. The machine population studied, however, was only those machines already in place in the building and was thus biased toward specific manufacturers. The authors noted that particle emissions varied substantially even among the same model of machine. According to Professor Morawska of the Queensland University of Technology, one printer emitted as many particles as a burning cigarette:<ref>{{ cite news | title = Particle Emission Characteristics of Office Printers | url = http://www.smh.com.au/news/technology/printer-particles-as-bad-as-cigarettes/2007/07/31/1185647903291.html | work = The Sydney Morning Herald | date = 2007-08-01 }}</ref><ref>{{cite web | title = Study reveals the dangers of printer pollution | url = https://www.qut.edu.au/news/news?news-id=13495 | access-date = 2017-08-06 }}</ref>

{{quote
| The health effects from inhaling [[ultrafine particles]] depend on particle composition, but the results can range from respiratory irritation to more severe illness such as [[Circulatory system|cardiovascular]] problems or [[cancer]].|}}

In December 2011, the Australian government agency [[Safe Work Australia]] reviewed existing research and concluded that "no epidemiology studies directly associating laser printer emissions with adverse health outcomes were located" and that several assessments conclude that "risk of direct toxicity and health effects from exposure to laser printer emissions is negligible". The review also observes that, because the emissions have been shown to be volatile or semi-[[volatile organic compound]]s, "it would be logical to expect possible health effects to be more related to the chemical nature of the aerosol rather than the physical character of the 'particulate' since such emissions are unlikely to be or remain as 'particulates' after they come into contact with respiratory tissue".<ref name='SFA_2011-12'>{{citation | first = Robert | last = Drew | title = Brief Review on Health Effects of Laser Printer Emissions Measured as Particles | publisher = [[Safe Work Australia]] | date = December 2011| url = http://www.safeworkaustralia.gov.au/sites/swa/about/publications/Documents/636/Brief%20Review%20Laser%20Printer%20Emissions.pdf | archive-url = https://web.archive.org/web/20170304205112/http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/636/Brief%20Review%20Laser%20Printer%20Emissions.pdf | archive-date = 2017-03-04 | access-date = 2013-10-23}}</ref>

The German Social Accident Insurance has commissioned a human study project to examine the effects on health resulting from exposure to toner dusts and from photocopying and printing cycles. Volunteers (23 control persons, 15 exposed persons and 14 asthmatics) were exposed to laser printer emissions under defined conditions in an exposure chamber. The findings from the study based on a broad spectrum of processes and subjects fail to confirm that exposure to high laser printer emissions initiates a verifiable pathological process resulting in the reported illnesses.<ref>{{Cite web|last=Institute for Occupational Safety and Health of the German Social Accident Insurance|title=Investigation on health effects of emissions from laserprinters and -copiers, Subproject LMU: Exposition of volunteers in a climatic chamber|url=https://www.dguv.de/ifa/forschung/projektverzeichnis/ff-fpa_0294-2.jsp}}</ref>

A much-discussed proposal for reducing emissions from laser printers is to retrofit them with filters. These are fixed with adhesive tape to the printer's fan vents to reduce particle emissions. However, all printers have a paper output tray, which is an outlet for particle emissions. Paper output trays cannot be provided with filters, so it is impossible to reduce their contribution to overall emissions with retrofit filters.<ref>{{Cite web|last=Institute for Occupational Safety and Health of the German Social Accident Insurance|title=Safe laser printers and copiers|url=https://www.dguv.de/ifa/praxishilfen/hazardous-substances/laserdrucker-kopierer/index.jsp}}</ref>

===Air-transport ban===
After the [[2010 cargo plane bomb plot]], in which shipments of laser printers with explosive-filled toner cartridges were discovered on separate cargo airplanes, the US [[Transportation Security Administration]] prohibited pass-through passengers from carrying toner or ink cartridges weighing over {{convert|1|lb}} on inbound flights, in both carry-on and checked luggage.<ref>{{cite web | url = http://www.myfoxny.com/dpp/news/international/uk-plane-bombs-explosions-were-possible-over-u-s-ncx-20101110 | title = UK: Plane Bombs Explosions Were Possible Over U.S | publisher = Fox News | access-date = 2010-11-17 | archive-url = https://web.archive.org/web/20120329061859/http://www.myfoxny.com/dpp/news/international/uk-plane-bombs-explosions-were-possible-over-u-s-ncx-20101110 | archive-date = March 29, 2012 }}</ref><ref name="pcmag1">{{ cite news | last = Hoffman | first = Tony | url = https://www.pcmag.com/article2/0,2817,2372313,00.asp | title = U.S. Bans Large Printer Ink, Toner Cartridges on Inbound Flights | publisher = PC Mag | date = 2010-11-08| access-date = 2017-08-06 }}</ref> ''[[PC Magazine]]'' noted that the ban would not impact most travelers, as the majority of cartridges do not exceed the prescribed weight.<ref name="pcmag1" />